In a surprise move, Burundian President Pierre Nkurunziza said on Thursday he would step down in 2020, despite widespread belief that he backed a new constitution extending term limits in a bid to cling to power.His announcement came shortly after he signed into law a new constitution, passed in a May referendum, that in theory allows him to seek another two terms in office."Our mandate ends in 2020," Nkurunziza said in a speech to supporters and diplomats in the central city of Gitega.Describing himself as "Guide" of the ruling CNDD-FDD party and referring to himself in the third person, the 54-year-old president said he would not seek re-election at the end of his current, controversial third term.In power since 2005, Nkurunziza's decision to run for re-election in 2015 plunged Burundi into a deep and deadly political crisis, with opponents saying his candidacy went against a peace deal that had ended more than a decade of civil war.Turmoil since then has killed 1,200 people, forced 400 000 to flee their homes and triggered an investigation by the International Criminal Court.Nkurunziza's third term has been characterised by growing authoritarianism, intimidation and abuse, according to human rights groups.Many political opponents have left the country for safety, while a sustained campaign against the press has forced most independent journalists also to leave.'Enemy claims' Last month Burundians voted overwhelmingly in a referendum in favour of constitutional changes, including extending presidential terms to seven years.The reforms also placed greater power in the hands of the president and was seen by critics as a death blow for the Arusha peace deal, signed in 2000.The changes were widely seen as a move paving the way for Nkurunziza to run for a further two terms under the new dispensation, allowing him to rule until 2034.But on Thursday Nkurunziza said that was not his plan."The new constitution has not been tailored for Pierre Nkurunziza, as our enemies claim," he said."As far as I am concerned, I am preparing to support, with all my strength, the new president who we are going to elect in 2020."A diplomat based in Burundi, speaking on condition of anonymity, described the announcement as a "nice political move".* Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and Facebook"It remains to be seen how sincere he is, because he is the one who launched the revision of the constitution and said he would be willing to run again if the people demanded it."He said after three years of crisis that have hit the economy hard, Nkurunziza "needed to give something to the international community to try and bring back financing." In neighbouring Rwanda, President Paul Kagame held a constitutional referendum in 2015, insisting it was not about his own desire to stay in power.However, he gave into what he said was the people's will and ran successfully for a third term two years later and is now permitted to vie until 2034.The European Union said Nkurunziza's announcement could ease the situation in Burundi.The president's move is "in line with the principle of democratic alternation as set out in the Arusha Accords and the African Charter on Democracy, Elections and Governance, and may de-escalate the situation in Burundi," said a spokesman for EU foreign affairs chief Federica Mogherini.The EU statement called for "a peaceful and consensual solution" which would guarantee credible elections in 2020.The opposition took Nkurunziza's announcement with a pinch of salt.Pancrace Cimpaye, spokesman for the exiled opposition group CNARED, said "the word of Pierre Nkurunziza, a man who buried the Arusha Accords and the 2005 constitution, means nothing."