the leaders of libya's new unity government return to tripoli but they face a fight for acceptance. this is al jazeera live from doha. also ahead, the u. is accepting more troops and tanks to eastern europe in response to what it calls russian aggression. colombia takes another step closer to ending its 50-year conflict. working nine to five on the line, it could be the end of the 35-hour working week in france

the leaders of libya's new u.n.-backed unity government have returned to the capital tripoli. they face a significant challenge to restore stability with different factions continuing to back rival organizations. >> reporter: defying threats by rival factions the head of the national accord arrived by sea to take up his position. >> translation: we were eager that there was no bloodshed in the process. we are committed to the terms of the political agreement that the libyans agreed on and we will expand the participants in it. >> reporter: but it wasn't welcomed by everyone. gunfire was heard shortly after unity government members arrived. >> translation: the government of national salvation calls on those illegitimate infiltrators

to either hand over themselves and be in safe hands or to go back to where they came from. salvation government is working with entities, all state institutions and ngos as well as community leaders to take the necessary steps to save the country from the threat of chaos and foreign intervention >> reporter: he had previously based in tunisia. whether he will be able to establish authority in libya will remain unclear >> the problem is that the government in tripoli, the government of the national salvation, is not unified. it is divided any way. there's another government too that in the east, in tobruk and that is divided as well >> reporter: the unity government formed under a u.n. peace deal lat late last year aimed to end the political chaos that existed since the up rising that toppled gadafe years ago. there are more obstacles in its

way. the islamic state in iraq and the levant have taken advantage of the political vacuum that has existed for years and have managed to find a new territorial foot hold in the i will-rich region. -- oil-rich. libya is also home to thousands of fighters belonging to several powerful armed groups which adds to the challenges the unity government would have to address to bring order to the conflict-ravaged country al jazeera's correspondent is in tripoli and says the dynamic in the capital right now is unpredictable >> to begin with, the fact that the opposition council has finally reached the new headquarters here in the neighbor base mere in tripoli. that is a big step ahead, but on the other hand each political

institution here either with the government or against the new government, each political institution, they have their own military on the ground. like what happened today, we heard shooting in the streets from brigades who are opposing their government of national accord, but we have heard recently that negotiations and talks are on to appease those brigades that are opposing the government of national accord. other than that, it's very unpredictable going to a libyan political analyst who says the political situation is unprecedented. >> for now we have three governments that all of them are operating out of libya or somewhere out of libya. what happens next is or what is supposed to happen next is that both of the other governments will hand to this internationally recognised

government, hand over power peacefully, but that does not look like an option at the moment, and as a result what we will end up with is instead of having two competing governments, we will have three competing governments in libya. why? because the government or the self-proclaimed islamist government in tripoli is refusing to hand over power and is going as far as actually threatening war and resistance against this u.n. backed government, and in eastern libya the other caretaker government has, prime minister has refused to hand over power because he said that this u.n. backed government was not endorsed by the parliament in the city of tobruk in eastern libya and as a result he would not hand over until it gets that endorsement from the internationally recognised parliament the u.s. says it's sending more troops and march tanks to eastern europe. the senior u.s. commander in

europe describes it as a necessary response to an aggressive russian. germany is likely to host the bulk of the contingent with the u.s. establishing a presence across six former soefant block countries. -- soviet block countries >> reporter: it constitutes the first permanent deployment of american ground forces along or near the russian front tear since the end of the cold war-- frontier since the end of the cold war. russia would not be a passive observer to this. russia has contended that this deployment is a violation of the 1997 treaty between russia and nato when it expande its membership, but it says that russia will respond asymmetrically, and it is said

that any attempt by nato to add ukraine or georgia to its membership would be met with severe consequences from russia here is a look at what this means. in 2013 the u.s. withdrew all its tanks from europe, but within months that decision was reversed at a training contingent of 22 tanks was returned to germany. that will now be increased more than tenfold to 250. the new hardware will be accompanied by more combat troops rising from 25,000 to almost 30,000. a former ambassador to nato says the u.s. move will offer reassurance to u.s. allies in eastern europe who may be nervous about russia's intentions. >> they ver concerned. they've been watching over the last several years. in 208 russia invaded georgia. it still occupies two of the territories there and has

recognised them as independent states. it invaded ukraine, it has annexed part of that territory and continues to support separatists in eastern ukraine, regularly violates the air and sea states and neutral countries in europe. it has threatened military attack, including nuclear attack against bar saw or against danish ships and the countries in the eastern parts, particularly the baltic states, are very concerned about this more aggressive russian behaviour. so for them it's very important that nato make clear that it maintains the political will and the military capability to fulfil its collective defense obligations. as long as that is true and visible, then we can continue to deter any russian aggression in the future. i think if anything it is going to cause russian to be more cautious in some of its approaches toward eastern allies and europe, and i think it you will understand and respect that the u.s. is taking a clear

position consistent with its longstanding treaty obligations of collected defense. what we've seen up to now in this part of the world is, i believe, russia taking advantage of the u.s. and nato. they've done everything possible to accommodate russia. what russia has done is go further and further from georgia, to ukraine and elsewhere. what i think we're going to see is a little bit more push back, programs, you could call it that, more persistence from nato, and i think that will help stabilize things a little bit rather than seeing this creeping russian - i wouldn't call it aggression necessarily in the case of nato, but creeping russian assertiveness which has continued because we have not responded world leaders have begun to arrive in the u.s. for a summit on nuclear security. more than 50 companies and international organizations are attending the summit in

washington. they will discuss ways to lessen the event of nuclear war and containment of nuclear materials. russia is not attending though. >> reporter: he flew to washington in 120 to take part in the nuclear security summit. he and his host obama agreed the time was now no keep nuclear materials away from the bad guys. >> translation: this is not about the economy. this is not global crisis discussion. this is the topic crucial for every state and its a real threat, a real challenge for all of us. >> reporter: but his skekor vladimir putin won't be joining-- successo won't be attending in march >> we hope that russia still

stands the view that the nuclear materials and combatting the threat of nuclear terrorism remains a priority of world leaders >> reporter: after the cold war russia and the u.s. worked to secure nuclear material in the former soviet nations as well as within russia. but russian security services long suspected the security program was a spying initiative in disguise and putin was more interested in undercutting him >> we have seen cooperation between russia and u.s. over the last few years on nonproliferation issues, if we're talking about north korea. in relation to iran, the russians have been central to the deal and the process there. i think they have this broader scepticism of u.s.-led international initiatives, particularly u.s.-led international institutions that might lead them to take a step back >> reporter: also at issue the u.s. sanctions in response to russia's annexation of crimea.

some are making what they call a calculation to skip the summit >> if an act of nuclear terrorism were to take place anywhere in the world, the entire international community would be affected by the environmental fallout, by the financial circumstances and certainly by the catastrophic loss of life. >> reporter: the russians are sticking by their decision saying the nuclear security summit has come to the end of its usefulness still to come here on al jazeera, brazil's embattled presidential has again accused her opponents of plotting a coup against her. a verdict is due later in the decade-long trial against an alleged serbian war criminal. we will tell you more. ll you more.

a moment to remind you of the top stories. the leaders of libya's new unity government have defied threats of violence to return to the capital of tripoli. the prime minister says he wants to achieve national reconciliation, but gunfire was heard shortly after they arrived. tripoli's self declared government and armed forces that back it say the entry of this u.n. backed government is illegal. the u.s. is sending more troops and tanks to eastern europe. the senior u.s. commander in europe described it as a necessary response to an aggressive russia. germany is likely to host the

bulk. a summit on nuclear issues and russia isn't attending. in colombia the government and the second biggest rebel group have announced the beginning of formal peace talks. the eln will follow on from the farc and take part in separate considerations with the government. the aim is to end 50 years of civil conflict. >> reporter: the missing piece to end the conflict. finally it will end the second biggest rebel group in the country agreed to start peace negotiations with the government. >> translation: they have agreed to open a public negotiating table to address the point on the agenda in order to reach a final agreement to end the armed conflict and agree to transformation is in search of a peaceful colombia

>> reporter: the announcement was made in the capital where they have been in talks since 2014. under the deal the public negotiations will take place in ecuador but some sessions will be held in brazil, chile, cuba and venezuela. >> translation: the action plan will involve mechanisms of control, monitoring and verification that will include the participation of society, the international community, the government and the national liberation army.{enter} q. the two sides agreed to a broad six point point agenda that will deal with issues like peace construction and the right of victims. the focus will be on public participation to define the most needed reforms in the regions affected by the conflict. some points will converge with the ongoing peace talks between the government and the biggest rebel group the farc that have been underway for four years in halve aborigine and in their final stretch. founded by a radical catholic

priest in 1964, the eln is a much smaller group than the farc but it has proved resilient and able to inflict damage. many say an agreement without the eln would have been fragile. with the dissidents switching, and taking areas under farc control. in a speech the prime minister said that bringing et ln to the negotiating table was paramount. >> translation: it will be the end of groups and we can concentrate on concentrating on making our country the free place it should be. >> reporter: at this point it is still unclear when the negotiations will begin in earnest. the government wants the eln to release any hostage they're still holding before agreeing to a date. what is clear is that this announcement means the country took another important step to a definitive and sustainable peace

brazil's embattled president has again accused her opponents of plotting a coup against her. more from our correspondent. >> reporter: the president dilma rousseff is fighting for her political survival. 24 hours half a major part pulled out, she unveiled new housing projects for the poor. she used the opportunity to push back forcefully against her critics and left in no uncertain terms how she feels about the impeachment process being waged against her. >> translation: impeachment without proof of crime of responsibility is what. it is a coup. this is the issue. there's no point predenieding that we're discussing a hypothetical impeachment. we're discussing a very concrete

impeachment. there's no point in discussing whether impeachment is or is not written in the constitution. it is. but what is not written is that without crime and responsibility impeachment can be perhaps legally and legitimately. natural imof that is coup >> reporter: here the special committee continues the impeechlt hearings. her popularity continues to plummet. on thursday more froefts are planned in a-- more protests ared the man accused of hijacking an egypt plane with a fake suicide belt has and in court in cyprus. egyptian national held up a plane on tuesday. he was remanded in custody for eight days.

egypt has requested his extradition. the international criminal tribunal for the former yugoslavia will deliver a verdict against serb i can't leader accused of stoking ethnic hatred during the wars in bosnia and croatia during the 1990s. >> reporter: serbian radical leader will not be in the hague on thursday when the judges pronounce his guilt or innocence of crimes against humanity. he will be in belgrade with the prospect of him being returned to the netherlands either voluntarily or otherwise looking remote. >> translation: brothers and sisters, i will not go back to the hague voluntarily, but i will use every opportunity, every moment, to inflict professional, political and moral damage to the hague tribal.

>> reporter: in 2003 he did surrender to the hague. over the past 13 years by a variety of means, he has taken great relish in snubbing and spiting the international court. first, he refused to enter a plea. he rejected legal representation and refused to accept the legitimacy of the tribunal. he succeeded in having one of the trial judges disqualified for bias, the first war crimes defendant ever to manage that. all of which somewhat over shadowed the gravity of the charges which are nine counts of crimes against humanity. he was described as a scandal master who mobilized his militia to terrorize, ransack and murder rival ethnic groups. tens of thousands of non-serbs were forcibly deported, sexually assaulted and beaten. in 2014 he was diagnosed with

liver cancer and persuaded the court to let him go back to serbia for treatment. he received a hero's welcome on his return. when the court in the hague decided to call him to prison in the netherlands, serbia refused to return him. uniquely his verdict will be delivered without him being in court. the international criminal tribunal apparently powerless to compel him. >> translation: this is a criminal who is laughing to our faces. we will react if it stays like this. >> reporter: he says he won't watching the verdict on television and doesn't care whether it's guilty or not. as he told a rally in belgrade earlier this year, i already beat the tribunal. paul brennan thousands of people are expected to demonstrate in france against plans which could affect the 35-hour working week. critics say that reforms will give unions less power and workers fewer rights.

supporters say that it will make france more competitive. >> reporter: they're known from being ideal for getting out of tight corners. a squeeze for tens of thousands of these smart cards are being produced here in france every year. when they arrive on shift they know they will be here later than they used to. the work has come to an end to try to give some extra hours are now being paid at a reduced rate. in return the company has promised to secure workers jobs until 2020. >> translation: right now this is a preventatidve move. labor costs is a major costs. it was important for us to stay

competitive. >> reporter: with 1800 jobs on the site, this is one of the biggest employers in the area. 15 minutes drive from here and you're in germany. some big french employers say that the 35 hour working week hinders competitiveness and that france needs to start acting like some of its european neighbors. the 35-hour working week hats been enshrined in french law since the year 2000, brauought by a socialist government it's a socialist president who wants to amend it, believing it will boost the economy. the proposals have alarmed the unions who wield significant power in france. the changes here divided union leaders but in the end most employees accepted them. >> translation: it is a

sacrifice for four years, but we didn't want to play poker with our jobs. we signed this deal and there are some sacrifices, but in the end we got job security. >> reporter: the government wants to press ahead with reform. a gear change which is likely to be testing for all sides involved. >> reporter: in greece refugees and local people of marched together to protest against the recent e.u. turkey deal. they were out on the streets of athens and the nearby port. under the deal refugees who arrive in greece from turkey could be sent back to their home countries if their asylum claim is rejected. demonstrators want european leaders to open up their border. cambodia's government says a multi government deal to take in refugees by australia has five. only five moved to cambodia under the program.

three have left the nation. now one of the last remaining refugees tell al jazeera that he also wants to leave. >> reporter: he has been badly persecuted here. he says he has been on the run all of his adult life. he hoped to start a new life in australia, but ended up in cambodia. >> reporter: this is a document that you signed saying that you would resettle in cambodia? >> translation: yeah. >> reporter: i've been speaking with minimum as part of a year-- him as part of a year-long negotiation. why did you decide to sign this? >> translation: i don't know. >> i don't know. i don't have anything >> reporter: you just wanted to leave nauru?

>> yeah. >> reporter: under a tough border protection policy, anyone who tries to reach australia by boat, is sent to pacific detention centers >> the message is simple, if you come to australia illegal by by boat, there is no way you will ever make australia home. >> reporter: with no viable resettlement options for refugees processed on nauru, australia signed a 42 million dollar deal with cambodia. the program was supposed to see dozens of refugees sent to the south-east asian nation, but only five people came. >> translation: i'm worried about how to live here. if i have to live here the way other refugees live here, how will i survive? >> reporter: three have already left. just four months after he arrived an rohingan man returned to myanmar. a few months later, a couple

went matrimonial home to iran. now only this man and another remain and he also wants to leave. the cambodian government admits the program has failed. >> of the five people who came to cambodia, three have left. is it a failure? >> you could say it's a failure, but they don't want to be here. they want to be in elsewhere, or they want to be in a country like elsewhere >> reporter: the australian government declined to comment. he understands little of the policies affecting his life and says he will keep looking for a place to call home you can see that report in full on al jazeera's 101 east which airs first later today at 2230 hours g.m. t. antarctica's ice might be

melting faster than thought. sea levels could rise over half a metre this century. results are challenging the u.n. climate panel's forecast where the sea level rise from the melting was estimated to be significantly lower. >> i'm ali velshi. "on target" tonight, america's cold war in the caribbean is fast coming to an end. the united states and cuba are taking steps to end more than half a century of disagreement. yet the embar go is in place. cuba is in the throes of change and the relationship with the