on the broadcast tonight, mideast mayhem. fighting and protests surge across the region in syria, yemen, bahrain and now jordan. we're on the ground with the latest. front lines. in libya, fighting on the ground and western attacks from the air, and we talk to the u.s. general in charge. under control. a new breed of air traffic controllers taking over with fresh questions about safety still in the air. and hanging tough. brave new worries about the crippled nuclear plant, but we find survivors of the japanese disaster giving everyone a lesson in resilience. "nightly news" begins now. captions paid for by nbc-universal television

good evening. i'm lester holt in tonight for brian williams. for a seventh straight day the u.s. and its allies bombarded targets in libya, still trying to break the back of moammar gadhafi's assault on rebel-held cities. the u.s. for its part says it's prepared to take a back seat, but exactly what the ultimate goal is and even who's in charge of this operation are still somewhat ill defined tonight. nato says it plans to take full command, but is still seeking consensus on a military strategy. in a moment we'll hear from the general in charge of u.s. forces there, but first to the ground where rebels are taking their own fight to gadhafi's forces. today nbc's richard engel joined them at the front lines and comes to us now from benghazi. richard, good evening. >> reporter: good evening, lester. today we were actually able to go south and moving through the desert to go behind the rebels' front line and enter the city of ajdabiya and see fighting inside the city itself.

through the desert behind the rebels' front line, we follow a secret convoy to bring water and fuel to the people of ajdabiya, a rebel city still partially held by gadhafi's forces. we reach ajdabiya's eastern gate. it's controlled by rebels, and marked by a tattered flag. ajdabiya is mostly deserted, an urban war zone. shops are closed or destroyed. there's no power or running water. just fighting between the revolutionaries and gadhafi's men, says this man. through a broken gate we enter his home. it was badly damaged by gadhafi's troops. this is shrapnel, he says, from the tank round that hit his house and went right in this room. and the fighting isn't over. outside we hear gunfire. gadhafi's troops are just a few blocks away.

we see rebels running, advancing. firing behind a wall. there is street-to-street fighting here in ajdabiya. we're taking cover behind a bus, as the rebels are trying to push out gadhafi forces that still hold large pockets of this city. the rebels reload in the middle of the street. it's hard to know where the bullets are coming from. open intersections are especially exposed. so we run through them. they say there are snipers on the road, so you have to go from cover to cover. the rebels advance, they reload, they hide behind whatever wall they can find, and then they push forward. the rebels remain poorly armed, but highly motivated. our goal is to free this city and all of libya from tyranny, said one fighter. as we leave ajdabiya, we see hundreds more rebels pouring in.

they're confident because now they're getting help from above. this gun camera shows a british warplane launching devastating attacks on gadhafi's tanks near ajdabiya. with air power and reinforcements, the rebels hope to capture ajdabiya within days. ajdabiya is significant, lester, because if the rebels can take it, it will be the first real sign of progress by the rebels since the western air campaign began. >> richard, we've heard these rebels described as rag-tag armies. are they beginning to operate as units? are they getting better weapons? >> reporter: the learning curve is very high. today we saw the rebels actually using some tactics. they have started to camouflage their vehicles using sand and mud so they're not as exposed. they are, according to the rebels, getting some new weapons and we even saw some multiple rocket launchers on the edge of the city for the first time. so, yes, they are learning, lester. >> richard engel in benghazi for

us tonight. richard, thank you. late last night nato agreed to take charge. no-fly zone over libya but many of the details need to be worked out before it expands its authority. earlier i spoke to general carter ham who leads the american effort. i began i asking him if nato would also take up the mission of directly protecting libyan civilians. >> well, i think that's precisely what nato will discuss in the coming days. again, it is my understanding that they have agreed in principle to accept that mission. the discussion over this weekend as to precisely how to do that, what nations will offer forces, under what rules will they operate, those kinds of matters to be decided. our role currently under my authority as the current commander is to make sure of two things. first, that we continue exercising the mission that we have in surveillance, and

secondly, that we are prepared to transition responsibility for this mission to nato quickly, effectively and without disruption to the ongoing mission. >> there is some disagreement among the allies as to how far to go to strike libyan ground targets. once everything falls under a nato umbrella, if in fact it goes there, will the u.s. have some latitude to strike unilaterally at targets that it deems fit? >> well, i don't think the u.s. would ever limit its military capabilities. i don't think that would be the case. but what we do as a member of the alliance and a contributor to this element, to this mission, the u.s. participates in those discussions and the nato alliance will come to an agreement as to how to exercise that particular mission. the u.s.'s role is envisioned to be one of contributing what we call unique u.s. military capabilities. >> does it bother you or concern you as a veteran commander that

you have troops engaged right now in combat and the political leaders are still working out not some minor details? >> well, certainly. in an ideal circumstance that before you commit u.s. forces or any forces to a campaign, you have a very, very clear vision of what your strategic end state is and how you're going to match those ways and means to achieve that objective. but sometimes the conditions don't allow you to have that discussion. and in this case, the regime was slaughtering thousands of civilians. i don't think it would be appropriate to wait and have that strategic discussion, albeit necessary, without intervening. >> general carter ham speaking to me earlier. he pointed out that the main mission continues to be to protect civilians. he says they are not offering any direct military support to the rebels. we've got late word from the white house tonight that president obama will address the nation on libya this monday

evening, a primetime speech from the national defense university in washington. elsewhere in the region, the arab uprising appeared to gather force today. protesters in syria, in yemen and in jordan took to the streets, and arab dictators fought back, sometimes with deadly force. ron allen joins us now from amman, jordan, with more. ron? >> reporter: good evening, lester. yes, jordan had been relatively quiet until a stunning outburst of violence here today. syria was even worse, with more dead and wounded on the streets, as so many people in this part of the world continue their fight for their rights and freedoms. as thousands of syrians took to the streets again today, a crackdown. witnesses say president bashar assad's security forces opened fire. more than 50 people killed, according to human rights activists, in the town of daraa, epicenter of the uprising. video posted on the internet the only images of the carnage. >> the only way that assad can stay in power is by being brutal.

he has lost his legitimacy. >> reporter: just yesterday a presidential adviser had promised a laundry list of reforms, higher pay, corruption investigations, a possible end to 48 years of emergency law. but clearly, many syrians are not buying it. in yemen, the crowds were even larger. hundreds of thousands demanding president ali abdullah saleh step down. saleh has lost key support in recent days. top military commanders and tribal leaders have joined the opposition, disgusted by a massacre last friday that killed nearly 50. today saleh was defiant, vowing not to hand over power. the u.s. counts on him to keep pressure on al qaeda in yemen and is reportedly trying to broker a deal. by phone a newspaper editor there said the president and the nation are running out of time. >> i don't think it will take more than a week. i believe that saleh will step down. it's either that or we could see a civil war in yemen after the week.

>> reporter: and now jordan. clashes between supporters and opponents of king abdullah, broken up by security forces. the violence happening as u.s. defense secretary robert gates was here urging the king to move faster on reforms. reforms clearly not happening fast enough for the thousands in the streets across the region. the security forces here in jordan quickly moved the protesters out. they are determined not to let jordan become like syria and yemen. lester. >> ron allen in amman, thanks. new concerns tonight about radiation in japan coming from those damaged nuclear reactors. trace amounts have now been picked up by air monitors in hawaii as well as stations in california, oregon, washington and colorado. authorities say it poses no threat to health. but in the quake zone in japan, the danger from radiation appears to be growing. nbc's chief science correspondent robert bazell reports. >> obviously things are not

contained completely at this time. >> reporter: there are serious new concerns about reactor 3 at the fukushima site, which uses highly toxic plutonium in its fuel mixture. japanese officials now say there is a high possibility that the third reactor's fuel rods are damaged and it is leaking radioactive water from the reactor itself or from the pumping system being used to try to cool it. there are also concerns about high levels of radiation at 1 and 2. japan's prime minister called the situation grave and says it does not allow any optimism yet. the problem at reactor 3 was discovered when workers stepped into water that had 10,000 times the amount of radiation typical for a nuclear plant. two of them were taken to a special radiation hospital. >> translator: when they said that the radiation level had gone up, i became worried. even though they say it's okay now, i'm still anxious. >> reporter: the events at the

reactor site prompted the government to expand the evacuation zone. initially those living in a 12-mile radius around the plant were ordered to leave, and those up to 18 miles away were urged to stay indoors. but now those up to 18 miles are urged to voluntarily evacuate. at the very least this will severely hamper the efforts to get the reactor under control. at worst, it will lead to the release of a lot more radiation into the environment, but not at the catastrophic levels that many had feared. >> even in the worst case, we are unlikely to see a release of radiation approaching that of the chernobyl accident. >> reporter: tokyo electric power has started injecting fresh water rather than saltwater into the pressure vessels of reactors 1 and 3 to avoid the possibility of corrosion. as an uneasy japanese population awaits more answers. robert bazell, nbc news, tokyo. so much for the gentle lamb. march is going out like a lion in a lot of this country. in the west, a huge storm has dumped more snow in the sierra

nevada mountains. the area is nearing all-time record snowfall levels. more rain and snow expected this weekend with flooding and avalanche warnings in effect in some places. another big storm system moving into the south where strong thunderstorms and tornados are possible. the fda today approved the first treatment shown to extend life for patients with late-stage melanoma or skin cancer. the drug is called yervoy and patients who took it lived an average of four months longer than others. but the fda warns of serious are side effects, including severe to fatal immune reactions. last year melanoma killed almost 9,000 people in the u.s. when we come back here tonight, with one air traffic controller falling asleep in the tower this week, who is minding the runways? a look at the new breed taking over in the tower. and later, more from japan. amid the disaster and the worries, signs of hope from people giving new meaning to the term "resilient."

air traffic controllers are in the news this week after that scare caused by a sleeping supervisor at reagan national airport early wednesday morning. the faa said today it's changing procedures and reviewing staffing in the wake of that incident. it's put a spotlight on a changing workforce as nearly half the veteran controllers in the system are reaching retirement age. now there's a new generation taking over. here's nbc's tom costello.

>> reporter: it's the daily choreography of pilots, planes and passengers, a scene repeated at 273 airports across the country every day. 35,000 flights, 1.7 million passengers. but to get here, you've got to start here. >> tango will extend downwind number 2. >> reporter: at the air traffic control academy in oklahoma city. >> cheyenne alpha zero. >> reporter: where the faa is pushing through a huge class of new controllers. >> 17 romeo, radar contact. >> reporter: it was the summer of 1981 when president reagan fired more than 11,000 union or patco controllers who went on strike. >> they have forfeited their jobs and will be terminated. >> reporter: then hired replacement controllers to take over. now 30 years after the patco strike, those replacement controllers are retiring in large numbers, and a new wave of controllers is taking over in both control towers and at radar screens.

today training involves sophisticated simulators that can lay out airport runways and traffic patterns in perfect gps detail. >> this runway here is runway 31. >> reporter: faa chief randy babbitt said no longer to controllers have to wait for real-life experience with congestion, snow, rain or fog. >> every problem that we think a controller might face, we can set up and run the scenario. >> reporter: and near disasters too. >> academy tower, hold short. >> reporter: arlene perez is training to move from a radar room to the huntsville tower. >> you just need to be able to think on the fly and make decisions real quick. >> reporter: the academy takes up to 18 weeks, then months or years of on-the-job training. >> here you have to keep your head on pivot at all times. you've got to constantly be moving. >> reporter: and the faa is now training a thousand controllers every year, as a new generation takes control of the nation's skies. tom costello, nbc news, oklahoma city.

on wall street today, stocks broke a two-week losing streak finishing the day and the week with gains. the dow was up 50 points at the closing bell. up next here tonight, the most formal dictionary of them all adds some new words that mighke yau out

today marks 100 years since one of the worst workplace disasters in u.s. history. 146 people, mostly young immigrant women, were killed in a fire in a triangle shirt waist factory in new york. some of their descendants remembered them today at the scene of the fire. the tragedy galvanized the american labor movement and led to many safety reforms. today's memorial became a rally for union workers pushing back against recent moves to curtail union benefits. some of america's best and bravest were in washington today to commemorate the 150th anniversary of the congressional medal of honor. more than 30 recipients of the highest award for military valor were on hand at a cemetery at arlington national cemetery. they also attended an event

hosted by joint chiefs chairman mike mullen at the pentagon. the law establishing the medal of honor was signed by president lincoln in 1861. the oxford english dictionary, the most formal and proper of them all has added some informal words to its lexicon tonight. text message favorites "lol" and "omg" are now officially words, along with that favorite "whassup" spelled with ss and not zs. yes, i did say that. some more normal words made it in as well. "taquito," those stuffed and rolled up tortillas, and the term "muffin top" made the list. according to oxford it's the flesh that protrudes above the waistband of a tight pair of pants. or what happens to you if you eat too many taquitos. it all comes full circle. when "nightly news" returns in a moment, a lesson in dignity from people who have lost everything.

finally tonight, it's been two weeks since the monster earthquake and tsunami laid waste to a huge area of northern japan. the death toll has now climbed past 10,000. many are still missing, many more homeless. but there is one thing the people of japan have not lost, hope. our report tonight from nbc's ian williams.

>> reporter: there's not much left of rikuzentakata, another coastal town largely obliterated by the tsunami. but here at last we found real progress in the relief operation. it is getting better, said the retired businessman overseeing this refugee center. what strikes you most is the sheer resilience of the people here. after all they have been through. it's all very orderly. there must be none of the chaos that frequently follows natural disasters elsewhere in the world. 800 people are living in this school. they're grouped according to the neighborhoods they were evacuated from. so as better to provide mutual support. we help each other, we depend on each other, he told me. that's how we'll get through this. keeping the children occupied is one of the biggest challenges. i try and make sure he's always having fun, this woman told me. teams of volunteers now serve simple but regular meals.

a medical center is treating mainly colds and flu and the first temporary homes are under construction. though there is still a shortage of warm clothes. we're all in the same situation, she told me. that's what gives us strength. the strength that momentarily evaporates in the privacy of a new telephone room providing for some a first link to the outside world. it will take a long time to rebuild, but this refugee center is a striking picture of dignity in the face of terrible adversity. ian williams, nbc news, rikuzentakata. that's our report for this friday night. thank you for being with us. i'm lester holt. i'll see you tomorrow morning on "today" and right back here tomorrow night. good night, everyone. -- captions by vitac -- www.vitac.com