donald trump's rivals ramp up their attacks after his controversial comments on national security and abortion. we'll go live to india where rescue crews are searching for survivors after an overpass collapsed. a groundbreaking architect zaha hadid has died. we look at her legacy. the u.s. women's soccer team sets a goal for equal pay. welcome to viewers in the united states and around the world. we're live in atlanta. i'm natalie allen. >> i'm george howell from cnn headquarters. "newsroom" starts right now.

and a good day to you. let's start with u.s. politics and donald trump, who is capping off what has been quite a controversial week. now trailing in two big polls ahead of tuesday's wisconsin primary. a fox business network survey released on thursday shows that ted cruz now has a 10-point lead over donald trump, 42 to 32%. >> only 19% of likely republican wisconsin voters support john kasich. this is the second poll this week with cruz on top. all of this comes as trump promises to bring the republican party together. cnn's senior white house correspondent jim acosta has more on trump's week of turmoil. >> reporter: even with his campaign in turmoil, donald trump was all smiles. crisscrossing washington in his motorcade, trump sat down with top rnc officials behind closed doors, later vowing in a tweet that he will bring the party

together, even as john kasich and ted cruz furiously tried to block his road to the white house. >> i have to tell you as a commander and chief and leader of the free world, you don't get do-overs. you need to be able to get it right the first time. >> reporter: kasich and cruz are now tag teaming trump over his gaffe that women should be punished if they undergo an illegal abortion, a position he abandoned hours later. >> do you believe in punishment for abortion? yes or no, as a principle. >> the answer is that there has to be some form of punishment. >> on a popular conservative radio show, cruz attacked trump as uninformed. >> i think it was just the latest confirmation that donald has not thought seriously about the issues facing the country, and he is willing to say just about anything to try to get elected. >> reporter: and while team trump was brushing off the abortion comments as merely a slip-up. >> there was a misspeak here and you have a presidential candidate that clarified the record not once, but twice.

>> it takes restraint. it takes judgment. it takes experience. not wild-eyed suggestions. >> reporter: kasich blasted trump for another jaw-dropping comment that he would not rule out using nuclear weapons in europe. >> i would never take any of my cards off the table. >> it is not the way that a leader of the free world or the commander in chief of our country to be so casually talking about the use, by the way, of nuclear weapons. it just shows that he is really not prepared to be president of the united states. >> reporter: looking to push back on that notion, the trump campaign confirmed the real estate tycoon met with his recently announced foreign policy team. >> and that's why i'm supporting ted cruz for president. >> reporter: back in wisconsin, the next contest on the calendar, cruz appears to be widening his lead, running a new ad featuring the state's governor, scott walker. still fuming over his war of the wives with trump cruz cracked a

joke on jimmy kimmel that proved the texas senator is not quite ready to forgive and forget. >> if i was get anything car and backing up and saw donald trump in mirror, i'm not sure what pedal i would pick. >> reporter: they called the talk productive. they talked about the state of the race and the upcoming convention in july, but no word on whether that gop loyalty pledge will somehow make a comeback. jim acosta, cnn, milwaukee. >> donald trump also met with his knew national security team thursday amid growing alarm over his policies. >> pentagon correspondent barbara starr explains why critics are worried. >> two of our -- >> reporter: president obama with japanese and south korean leaders urging a unified front against nuclear north korea. >> we recognize that our security is linked, that we have to work together to meet this challenge. >> reporter: donald trump has a different idea. >> at some point we have to say

you know what this we're better off if japan protects itself against this maniac in north korea. >> reporter: trump says japan and south korea should pay the u.s. for security protection or consider building their own nuclear weapons, which would be a major policy reversal for the u.s. >> where trump's comments are most potentially dangerous is, again, getting away from the assumption that once the genie starts to leak out of the bottle again on nuclear proliferation that we can control where it goes. >> reporter: trump also raising another potential nuclear scenario. he says he wouldn't take nuclear weapons against isis off the table. >> would there be a time when it could be used? possibly. >> reporter: the deputy commander fighting isis doesn't think nuclear weapons are a good idea. >> no, that's a conversation up-front i've never heard discussed amongst any of our coalition members at any stage. >> reporter: also raising

eyebrow, trump's belief troops are afraid of being held accountable under the international rules governing humanitarian treatment of the enemy in time of war. which enemies like isis don't obey. >> the problem is we have the geneva convention. we have all sorts of rules and regulations. our soldiers are afraid to fight. they don't want to go to jail because they're killing the enemy. they were too tough. so we have all sorts of really restrictions and regulations. they have none. >> reporter: it's not a new argument, but commanders say there is no direct evidence of that. >> i've never heard of soldiers afraid to fight because of geneva convention in that regard. we regard it very much as a sense of basic principles which guide our behavior in battle and to live within those rules i think is good for both our soldiers and indeed the very population that we fight on behalf of. >> reporter: and another military challenge from the top american officer to trump's view that nato is obsolete. >> i think that question

probably is a question that might have been asked 15 years ago. but it's hard to think about asking that question today when you look at the challenges in europe. >> reporter: the military has been trying to stay out of the presidential campaign, but these national security questions keep coming. trump keeps making news. and the pentagon struggles to answer. barbara starr, cnn, the pentagon. >> so when it comes to that very all important issue of nuclear weapons, world leaders for more than 50 countries are meeting in washington with the gel of achieving global nuclear peace. friday is the second and last day of the nuclear summit. >> and u.s. president obama met chinese president xi jinping. china a key economic ally to north korea, and beijing has been criticized before for not doing enough to enforce western sanctions against north korea. >> of great importance to both of us is north korea's pursuit of nuclear weapons, which threatens the security and stability of the region.

and president xi and i are both committed to the denuclearization of the korean peninsula and full u.n. implementation. how we can discourage nuclear tests that escalate tensions and violate international obligations. >> our paula hancocks joins us now from seoul with more on the meetings, expectations from them, and certainly north korea's intention. paul lab, hello. >> hello, natalie. it was a crucial meeting between president obama and between the japanese and south korean leaders. certainly the japanese and u.s. officials did mention that trump's comments would not dealt with within that meeting, just to put that into perspective. but they did talk, obviously, about north korea and about what we've seen from north korea this year, notably a nuclear test in january, and of course that satellite launch, widely seen as a missile test in february.

followed by many photos and pronouncements by north korea that they have miniaturized a nuclear weapon and many other issues. certainly that was the key to this meeting. we heard from obama saying that all three agreed that they had to restore a sense of stability and peace to the region. we heard from south korean president park geun-hye as well and she said it was important to make north korea understand that it cannot survive without giving up its nuclear program. obviously, the one focus as well was the u.n. sanction, whether or not they would be implemented fully. president park did say that that was vital that they said it was implemented fully to try to have an impact on that nuclear program. natalie? >> have there been any new ideas floated that we know about at the summit with dealing with north korea and trying to figure out how to keep them from their continued provocative acts? >> well, i think it's tricky for them to be able to come up with

anything new. obviously north korea and its nuclear program is something that has concerned much of the international community for years. and so i think something new would be unlikely. we did see, though, what many called unprecedented sanctions by the united nations security council. and i think the crucial thing now is to see whether or not they are implemented fully. some experts say it could be the end of this year before we actually know if they're being implemented fully. of course, china is key to that, sharing that very large border with north korea. much of the trade goes through china. and according to xinhua state news agency in china, they said that president xi stressed all parties to fully and strictly carry out the u.n. resolutions. so they're reporting that china's president wants this -- these sanctions to be implemented fully. and of course that's music to the ears of the rest of the international community, because they know that it's crucial that china fully implements the sanctions. if they don't, there is very little chance of them making any difference at all to the nuclear

program. >> a critical player in that regard for sure. thank you, paula hancocks, live from seoul for us. >> you're watching "cnn newsroom." still ahead this hour, rescue crews are on an urgent mission in calcutta, searching for dozens of people still missing after a highway overpass collapsed. we'll take you live to the scene there. also ahead, health officials gather to plot an action plan against zika, we get an inside look at the lab that pinpointed the virus and its devastating effects on pregnant women and their babies. that's coming up. every day you read headlines about businesses

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welcome back. a police training exercise went horribly wrong in the u.s. state of virginia when a man pulled a gun and fatally shot a state trooper. trooper chad dermeyer was part of the training at a bus station in richmond. the 37-year-old was shot multiple times after he walked up and started talking to the suspect. dermeyer leaves behind a wife and three young children. >> police shot the suspect, who died on his way to a hospital.

they don't have a motive yet and they haven't released the shooter's identity. on to india now. at least 22 people are confirmed dead after a highway overpass collapsed on to a busy marketplace in kolkata. rescue teams are trying to find anyone trapped in the debris there. 75 people are injured, some critically. dozens of others are still missing. cnn is in kolkata where the rescue efforts are taking place and joins us this hour. ravi, i know you're in the heart of it all where things are happening. what are you seeing? what is happening around you now? >> reporter: hi, george. it is almost noon here. so about 24 hours since the bridge first collapsed. i just want to give you a sense of what is behind me and where i am. so right behind me, you obviously see the rubble that is being brought in. and that is rubble from the bridge that just collapsed behind me. if it were still there, you would have seen the bridge cutting across the open space. you see the old houses behind

me. they were just feet away from the bridge when it did collapse. about 100 or more national disaster relief forces are here. they're working with the west bengal police. west bengal is a state of which kolkata is a part. and they have been working through the night, trying to rescue any bodies they can find. so far they have rescued two bodies, but sadly, both of them were dead. the bodies were mangled and bloody. they're beginning to loose hope that they may not be able to find any people who actually survived this collapse. and it really is a real tragedy for the city, which has seen a spurt in these kinds of overpasses or flyovers as kolkatans call them. as cal kata has tried to come to grips with more growth, connect itself to suburbs. this one here, though, is an

overpass that has had many delays. it's been built over the course of five years. it was still under construction when it collapsed. >> the prime minister there, narendra modi tweeted he was, quote, shocked and saddened by what happened. an executive for that company that built that flyover calling it, quote, an act of god. but when this comes to how it happened and why it happened, who is pointing the fingers at who? >> well, we don't really know why it happened yet. if it was an act of god, well you could have maybe pointed to an earthquake or a storm or something like that. but none of those conditions were in place yesterday. so we can't stand up that claim from the people who built the bridge. on sunday, sorry, yesterday, when the bridge did collapse, the chief minister of west bengal was here within a few hours. she was trying to direct the movement of traffic and trying to bring help to people who

needed it. but locals here and residents and eyewitnesses tell me it was many hours before the rescue trucks, the tractors came in to try to clear the debris from this area. so it was a delayed start in many senses. and if you think about it, these roads are so narrow. it really isn't a surprise that it's hard to get here. and the bridge itself, it seems quite shoddy. and the way it's constructed very near buildings quite dangerous. many residents i have spoken to here, they really don't understand why it was built in the first place, that they're not very happy with the construction. you can see behind me, i think it's one of the local mps walking by, trying to attest the damage. but really, there is a larger political blame game that is now beginning to play out here in kolkata. west bengal, the state, is going to have assembly elections next week. so already on the indian tv shows there is a lot of finger-pointing going on. the fact remains, though, this

is still a developing situation. there are still people trapped here. and clearly, you know, very tense, desperate rescue efforts still under way that is the first priority for everyone i had been speaking to here. george? >> just before noon there in kolkata, where the rescue effort is still under way to find other people who may be miss organize trapped in that debris. live for us, thank you for your reporting. now on to this. >> this is the latest in a string of deadly bridge failures across india. in 2009, 45 construction workers were killed when this partially built bridge gave way in northern india. in 2006, a 150-year-old bridge collapsed over this express train in bihar state. at least 33 people were killed. and in 2005, more than 110 people died on a passenger train. a small railway bridge had been washed away by flooding, causing this express train to plunge

into a river. in the united states, there is a target for health officials. it is the zika virus. very important here. the u.s. centers for disease control and prevention is hosting a zika action plan humt summ summit, and their same to come up with a coordinated response to deal with the growing threat. >> the cdc says active zika infection has been identified in 39 countries and territories worldwide. a health alert was issued after the first brazilian zika case was confirmed in may of last year. since then the virus has spread through much of the americas. >> when it comes to pinpointing an organism like zika with the potential to cause devastation around the world, it is a huge challenge. >> cnn chief medical correspondent dr. sanjay gupta visited the cdc lab that first linked the zika virus to

microcephaly. >> reporter: at the centers for disease control. >> december, one week contacted by our colleagues in brazil about looking at some cases of children who were reporting with small brains or microcephaly. and see if there was an association of the virus infection. >> reporter: what happened is they received samples from two miscarriages and two infants who died shortly after birth. all the mothers to be had the mosquito-borne virus while pregnant. >> we got the first pcr results. i couldn't believe it at first. four out of four were positive for the virus. so that's the virus there in the brain. >> that's in the brain? >> that's in the brain. you can see other area with the virus. >> this is the first sample. you looked at a child who was born and died within 24 hours? thinking was the first case that we actually saw it in the brain of one of the children. >> this is really what made the case. >> yes. >> that zika was associated with these problems. >> reporter: and that's important, because correlation does not equal causation, as they say. in order to be sure, they're going to need more time. and unfortunately, more people

infected. he says it's like piecing a puzzle together. >> it's a huge team effort. we have 30 staff members, including pathologist, molecular biologist, epidemiologists, talking about cases, what do you think is real? it is not real? what kind of infection are you suspecting in a particular case. we depend a lot on clinical information. it's not just looking at the slides, but we have to put it all together. nobody can be 100% sure. you always have to keep in mind could it be something else that could explain this and explore those possibilities. >> reporter: the first i saw the virus, there was dread in the room. >> i want to say excited but you also have to feel devastated about we always look at the case and think of what we're seeing. but there is always somebody behind that. and outcome is sometimes not good. so you have to think about that in relevance and to see the pictures of these babies that are being born in some videos that are just very heartbreaking.

>> reporter: none of this is unfamiliar. he has been involved in nearly every major disease outbreak and discovery throughout his three decades with the cdc. >> i've had a lot of experience with the anthrax back this 2001 or hantavirus or nipa. so you're seeing it for the first time. >> reporter: even with all you're seeing, he says it's not an infectious disease that keeps him up at night. >> my worry is always about missing the diagnosis. i wake up at night sometimes. did i do this wrong? did i make sure everything and all the i's are dodotted and t' crossed. >> these pictures? >> yes, over the years. actually these were -- this is a case of spotted fever. if not treated, it's fall. >> reporter: how about this one over here? >> this is a fungus ball in the lung of a patient who was

immunosuppressed. it's called aspergillis. >> are you going to have zika on the wall? >> yes. >> reporter: dr. sanjay gunpoint tax, cnn, atlanta. a new global study shows more than one in eight adults are obese, and that number is only going to get worse. the study published in the lancet says by 2025, one in five adults will be obese. >> still, the authors say excessively low body weight is a serious concern in the world's poorest regions. they say the obesity epidemic shouldn't overshadow the problem of people not getting enough to eat. >> there has been a lot of talk about a contested republican convention in the u.s. presidential race. >> we'll seattle. >> up next, we break down the numbers to see how likely it could be. plus, the toughest contest of their careers. players from the u.s. women's soccer team sake their claim for the same pay as their male counterparts. we'll tell you why the math is

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and welcome back. you're watching "cnn newsroom" live from atlanta. i'm natalie allen. >> and i'm george howell. the headlines we're following this hour. this just in to cnn. we're learning of yet another missile fired by north korea. the south korean military source says pyongyang has fired a short range missile which landed in the sea off the east coast of the peninsula. this comes just hours after north korea's neighbors called on the regime to end such provocations. pyongyang has been heavily sanctioned by the west for its recent missile launches and nuclear tests. other top stories for you now. in india, rescue crews are searching frantically for any survivors in the rubble of a collapsed highway overpass in kolkata. at least 22 people are dead. 75 others injured. the bridge was under

construction in a crowded neighborhood. the united states and china are pledging to work closer together to achieve nuclear security. the chinese and american presidents met during a nuclear summit in washington, d.c. china plays a key role in enforcing sanctions against north korea, which has nuclear weapons. minimum wage earners in new york will be getting a raise. the governor and legislature have agreed to phase in the state's minimum wage to $15 an hour by late 2019. u.s. presidential candidate donald trump met thursday with the head of the republican national committee. >> the party source says they talked about delegates. they talked about convention rules and the state of the race. our ryan nobles takes a look at the numbers involved to get that republican nomination. >> reporter: donald trump is currently in the best position to win the republican nomination. but he may need every day of the primary process in order to seal the deal before the convention comes to cleveland in july.