on the broadcast tonight, shifting sands. the shock waves now in the middle east now forcing the u.s. to make some tough choices. a first look inside the rehab facility where congresswoman giffords is working hard to get her life back. outbreak, something is slowly killing off some of florida's greatest treasures, and incredibly it's related to the economic crash. and high note. we know jill scott is a grammy award-winning singer, but wait, there's more to her story. "nightly news" begins now. captions paid for by nbc-universal television good evening.

we've been covering our lead story tonight, steadily watching it grow and what started in cairo, the uprising, we saw before our very own eyes has now spread to libya, among other places, where it is shocking to see a depiction of moammar gadhafi on fire, but there it is. pictures from social media making their way from the internet to us and then around the world. this chain of nations where a lot of rulers fear they may be next also makes it tough for the u.s. in knowing how to respond and when. again tonight we go to cairo. we begin with our chief foreign affairs correspondent, richard engel. richard, good evening. >> reporter: good evening, brian. the middle east has simply never seen anything like this before. every day we are now looking at a map, trying to figure out where this is going. for now, it seems to be yemen, bahrain and libya. [ chanting ] >> reporter: the shock waves from egypt are still spreading.

today libya saw the worst of it. in benghazi, libya's second largest city, protesters were furious tuesday night at the arrest of a human rights activist. a video then appeared online today claiming to show gunfire in the city this morning. it's difficult to tell who's firing and where. the libyan unrest, like in egypt, is organized online, with videos like this one showing moammar gadhafi with the ousted leaders of tunisia and egypt. gadhafi, in power for 41 years, was once considered the united states' main enemy in the middle east. in a potentially dangerous concession to protesters today, libya released 110 islamic militants from prison, including the brother of one of al qaeda's top commanders. we spoke to the brother by telephone.

he told us the libyan militants are not a threat to the west. protesters are calling for a day of rage in libya on thursday. in iran, there were clashes today at a funeral for a protester killed on monday. the government is taking a hard line to stop the protests, calling for the execution of opposition leaders. nbc's ali arouzi is in tehran. >> reporter: richard, opposition leaders went online today to say they were unafraid and to thank protesters for turning out on monday. later today the internet in iran was slowed almost to a halt. >> reporter: and at night, the sound of defiance has returned. cries of "god is greater" shouted from tehran's rooftops. the hallmark of a similar uprising in 2009. in yemen, a country where the united states would likely

prefer reform to regime collapse, protests continued for a sixth day. a police truck drove through crowds to disperse them. the united states supports the yemeni government. without it, al qaeda could have an even bigger sanctuary in yemen. protests are also spreading in bahrain, a tiny but crucial u.s. ally. demonstrators today held a funeral for one of two people killed this week. thousands of protesters are also trying to copy egypt's revolt, camping out in the main square of the capital, manama. "the new york times" nicholas kristof was there. >> reporter: richard, there were huge and growing crowds today. there was no violence largely because the police pulled back and seemed to avoid confrontations after the previous deaths. it was also striking how many women there were involved in the protests. >> i'm here to be with my brothers and my sisters. we want democracy, we want a free country. >> reporter: trouble in bahrain could further destabilize the

region and u.s. interests. bahrain is the base of the navy's fifth fleet and has a sectarian divide. the royal family is sunni. 70% of the people and nearly all of the protesters are shiites. the same explosive mix as in iraq. protests are spreading there too. iraq was supposed to be the model for democratic success in the region. but iraqis complain about corruption and the lack of services and security. major demonstrations are planned against the iraqi government next week. and here in egypt, brian, demonstrations are supposed to start again on friday to celebrate, but also warn the army that the people here expect democracy. >> richard engel after another wild day across that region. richard, thanks. the question is how does the u.s. respond to what is going on across the middle east where no two of these circumstances is alike. our chief foreign affairs

correspondent, andrea mitchell, in our washington newsroom tonight. andrea, you heard richard say it. something like this never happened in the middle east before now. >> reporter: it's unprecedented. it is amazing. the u.s. is now trying to respond to the dizzying pace of change in the region, but, brian, it is not an easy adjustment. there has been criticism that the administration was slow to recognize the strength of the protest movement in egypt. and for a while, it sent out mixed messages out of concern for what it thought was stability and perhaps misplaced loyalty to other arab strongmen. u.s. officials say they have consistently been pressing even their closest allies to reform but they were constrained by strategic alliances. now they are telling governments in bahrain and jordan that small reforms will no longer be credible and they will be vulnerable too until their young, educated and jobless population see real progress. their approach, though, is very different in iran. unlike the administration's ambivalence during the green revolution you saw in richard's

spot back in 2009, this week president obama strongly supported the dissidents and accused the regime of hypocrisy. for applauding the protests in egypt but repressing them in iran. the administration has also tried to work around iran's internet restrictions and launch twitter feeds to help the dissidents. they don't expect regime change but they think the protest could further undermine it. >> andrea mitchell on how the u.s. is dealing with this unbelievable time. andrea, thanks. last night here on this broadcast we talked about food prices, around the world and here in the u.s. and tonight we have a big story out of florida related to that. this is about a natural disaster, assisted by mankind that is threatening a great american industry, the citrus crop, a huge component of the florida economy. and it's spreading. as you're about to see, while this is affecting agriculture, it's related to the economy and the housing crisis. nbc's mark potter has our report

tonight from lakeland, florida. >> reporter: in central florida, citrus is huge. a $9 billion a year industry with 76,000 jobs. but now that industry is threatened by something growers can barely see. >> it can kill trees in up to two years. i'll tell you what, growers are worried. >> reporter: the disease is called citrus greening. it disfigures the leaves, chokes off nutrients and makes the fruit inedible. >> it is the most serious issue we have ever faced. >> reporter: it is spread by this tiny insect, the asian citrus psyllid, which arrived in florida 13 years ago. scientists discovered the disease here in 2005, and blame its rapid spread on the unwelcome pest. >> psyllid is highly mobile. it flies away from citrus every month of the year. >> reporter: to combat the disease, many growers use a combination of pesticide and fertilizer. but what they can't control is that among the half million citrus acres being cultivated

carefully are 145,000 acres that are uncared for. during the real estate boom, a lot of groves like this were sold to developers, who planned to remove the trees and use the land to build homes, hotels and shopping centers. but when the boom went bust, the groves were abandoned and trees were left to die, becoming perfect hosts for the disease-bearing insects. >> this is a breeding ground here and it's just going to fly across the ditch and reinfest me. >> reporter: billy keel is right next to infested groves. >> we're over here trying to control it where this guy is not. you know, they fly over here and fly back and forth. >> reporter: in some areas, growers are actually paying for crop dusters to spray the abandoned fields, but where they can't do that, they're having to work overtime just to stay ahead of their biggest threat yet. mark potter, nbc news, lakeland, florida. and there is an investigation tonight into an attack on two u.s. federal

agents in mexico in the line of duty. one of those agents was killed in the attack. telemundo's jose diaz-balart is in mexico city tonight with new information. >> reporter: brian, this is the highest profile attack on u.s. lawmen since 1985. one of the customs agents was shot five times in the abdomen and lower body and died on his way to the hospital yesterday. the second agent was badly wounded and has since been flown to the u.s. for treatment. sources close to the investigation tell nbc news that the two agents were traveling in the afternoon from the u.s. to mexico city to deliver supplies. they were in an armored suv with diplomatic plates driving through the monterrey area. nbc news and telemundo have learned the agents noticed they were being followed by two suvs which then came up aggressively behind them. sources say the gunmen blocked the road, forcing the agents to stop. one of the gunmen entered the stopped car and shot the agents at close range. the suspected drug cartel hitmen

left the agents for dead but the wounded agent was able to call for help. law enforcement sources say questions have been raised as to why the agents stopped. how the gunmen got the into the armored vehicle. what may have been stolen from the vehicles. and if all security procedures were followed. sources believe the zeta cartel is responsible for the attack. late today secretary of homeland security janet napolitano and attorney general eric holder announced the creation of a joint task force to coordinate with mexican authorities so they can bring those responsible to justice. brian. >> jose diaz-balart from telemundo. thank you for that report tonight. when our broadcast continues on a wednesday night, the whole nation has been following her story of courage and grit. next we'll go inside the hospital where doctors show us what gabrielle giffords is doing and why it may be the hardest work of her life. and later, a star with the voice and the vision and who is giving people a shot at a better life.

as we mentioned earlier tonight, we have learned more about the recovery, therapy and treatment for congresswoman gabby giffords. we also now know she's been given little detail on the shooting, what happened to her. her doctors want to wait until she is further along in her recovery. and we know a little more about her average day. many hours of therapy. we got a rare look inside her rehab facility, houston's tirr memorial hermann where she's been speaking short sentences credited to intensive speech therapy and music. ♪ you are my sunshine, my only sunshine ♪ >> the already athletic giffords undergoes rigorous daily physical therapy, squats to rebuild her muscles and an innovative way to learn balance and walking again by using a shopping cart. >> if you put someone's hands here, they're not going to walk

this way, they're going to walk upright. so it's a way to trick the body. it's a more natural movement for the patient to be using this. >> giffords is also watching a little television. apparently she and her husband, mark kelly, watched "30 rock" together just last week. for more on gabby giffords' rehab facility, there's more material available on our website, nightly.msnbc.com. well, it's official, several eastern states were lit up by a rare broad daylight meteor this past monday. just after 12:00 noon it streaked across the skies of pennsylvania and new jersey and headed right for the atlantic ocean. it was estimated to be the size of a car. police departments got phone calls about a bright object, even brighter than the noontime sky, rare but not unheard of. lance armstrong said today he's retiring from cycling for good. says he really means it this time. armstrong is 39 years old, he's got five children, seven victories in the tour de france.

he's survived cancer and now he's the subject of a federal doping investigation, though he says that has nothing to do with this retirement decision. it's been, he said today, an excellent ride. a victory for consumers everywhere. here's a story for every person who's taken out a credit card at the cash register and been asked for your zip code. have you ever wondered why they ask? why in order to buy a pack of gum do they first need to know where you come from? of course it's for their own marketing and research, but let's hope it stops now. a week after the supreme court of california ruled in a case involving williams-sonoma, that stores may no longer ask customers for their zip codes as part of a transaction, now more than a dozen new lawsuits have been filed against big names like walmart, bed, bath and beyond and crate and barrel. and borders books is the latest victim of the rise of ebooks and online retailers like amazon. borders, part of the walden

books family and the second largest bookstore chain in the country, has declared bankruptcy. says it plans to close nearly a third of its stores. sales just haven't been good enough lately. they were never able to develop a robust web presence and they have been holding back on payments to landlords and publishers. could it be, could help be around the corner for the common cold? when we come back, a reality check on that. a few other health stories in the news when we all woke up this morning.

there were a couple of health stories today you might have heard something about this morning. the first one had to do with zinc, which as you may know is marketed for the common cold as lozenges and other forms. british researchers took a closer look at 15 separate studies and after adding up the pros and cons concluded that taking zinc on the first day of

the onset of a cold can make a difference. >> it does seem to show some evidence that taking zinc may reduce the severity and the duration of symptoms of a cold. >> zinc can also reduce the length of the average cold by about a day in all the experts found. but should you take zinc every day to reduce the chances of getting a cold in the first place? no, they say that could be harmful to your health and it doesn't work that way, but look for a run on zinc lozenges. and there's this one, news from a french study that men who show signs of balding in their 20s are twice as likely to develop prostate cancer in their lifetimes. it's a small study but the results are not surprising to the experts we're told because men with high levels of testosterone are already known to be at risk for both, early balding and prostate cancer. and finally something a lot of us take a lot of in, caramel coloring, the stuff that makes

coke and pepsi and other soft drinks so dark. not actual caramel, just the color. a consumer group says some versions of caramel coloring contain chemicals that could cause cancer and should be banned. the trade group that represents america's beverage makers calls the claim, quote, a scare tactic and says there is no proof of the claim. up next here tonight, aren't the best stars always the ones that never forgot where they came from? well, we'll introduce you to one tonight.

we've been marking black history month along with our partner website, thegrio.com and its list of 100 history makers in the making. one name on the impressive list is the impressive jill scott, the globally known grammy winner. but tonight you get to find out why a singer is on the grio list in the education category. our own mara schiavocampo caught up with jill scott in l.a. where she's working in the recording studio these days. >> reporter: as jill scott records her latest album, one thing is clear. her songs are as much about the meaning as the melody.

>> i enjoy making music that is more human than perfect, more soul-filled rather than soulful. >> reporter: scott finds inspiration in life's ups and downs. raised in philadelphia by her mother and grandmother, who was affectionately called "blues babe" scott started writing poetry in the seventh grade. the young poet was also an aspiring singer, and got her start by working in a recording studio, restoring the wood in the lobby, waiting to be noticed. >> every day i would stain and polyurethane. >> reporter: needless to say, it worked. since her debut album in 2000, she's sold four million albums, won three grammys, and expanded her reach from the stage to the shelves to the screen. >> you are my past. >> reporter: starring in two tyler perry films in the hbo series "the number one lady detective agency." >> you have come to the right place.

>> reporter: but scott is most proud of this. the blues babe foundation started in 2002 and named after her grandmother, the charity has given a quarter of a million dollars in grants and scholarships to students in the philadelphia area. like katherine morris, an honor student who was only able to graduate from temple university with an emergency scholarship from scott's foundation. >> i would never cross that stage. i would never be able to stand in front of my peers and just say i finally made it. >> if everybody takes part and joins in in their neighborhood, where they grew up, where it was wonderful or terrible, we make a difference in the society. ♪ >> reporter: using her voice to change lives just as it has touched them. mara schiavocampo, nbc news, los angeles. there's more on jill scott's story, including an extended interview with her and information on the entire and

impressive group of the grios 100 history makers in the making. it's on the web at thegrio.com. finally tonight, the winner is -- >> best in show is the deerhound. >> a scottish deerhound named hickory with a bit of a beard made history by taking best in show at this year's westminster dog show here in new york. it's the first time the breed has ever been named grand champion. a very proud doggy. hickory's victory lap included filet mignon lunch at sardi's restaurant here in new york. failed to leave a tip, something about not having a wallet. that's our broadcast for this wednesday night. thank you for being here with us. i'm brian williams. as always, we hope to see you right back here tomorrow evening. good night. -- captions by vitac -- www.vitac.com

for people across the bay area, from downed trees to hail and some big waves there. and this is only the beginning of this type of weather. good evening and thanks for joining us. i'm diane dwyer in for jessica aguirre tonight. >> and i'm rog mathai. it's been an eventful day of weather here in the bay area. rain, wind, and cold air. that was