Despite a string of grenade attacks in polling stations, voting in Burundi's controversial elections opened on Monday despite , the latest in weeks of violence sparked by the president's defiant bid for a third term.
Assailants threw grenades at stations in both the capital Bujumbura and in some provinces ahead of Monday's parliamentary and local elections, delaying the start of voting in many of the centres, police and election officials said.
UN Secretary General Ban Ki-moon has called for the elections to be delayed after the opposition said they would not take part, as Burundi faces its worst crisis since its civil war ended nine years ago.
"Armed groups tried to attack polling centres... they were shooting and threw grenades, but the police stopped them," deputy police chief Godefroid Bizimana said.
Stations for the parliamentary and local elections opened late in some areas, although election commission spokesman Prosper Ntahorwamiye insisted that, apart from some delays due to the violence, voting was "going well."
"Voting has not yet begun in many centres in the capital because election officials are trying to prepare materials and in almost all of the stations, these arrived late because of the overnight attacks," said election commission chief in Bujumbura, Cyriaque Bucumi.
On the eve of the election, top party official and parliament head Pie Ntavyohanyuma said he had joined some 127,000 other Burundians who have fled the country, denouncing President Pierre Nkurunziza's "illegal" bid to stay in power for a third term.
Burundi was plunged into turmoil in late April when Nkurunziza launched his drive for a third consecutive five-year term, triggering widespread protests.
Opponents say his bid for another term is unconstitutional and violates a peace accord that paved the way to end 13 years of civil war in 2006. Presidential polls are due on July 15.
"The mandate he wants to have is illegal. I would like to say to him that forcing through the election is senseless," Ntavyohanyuma told the broadcaster France 24 on Sunday.
More than 70 have been killed in weeks of violence and a failed coup sparked by Nkurunziza's bid to stay in power, with a string of grenade attacks in recent days.
Several top officials, including the deputy vice-president Gervais Rufyikiri as well as members of the election commission and constitutional court, have also fled the poverty-stricken, landlocked country.
The African Union has refused to send observers to the polls.
"Noting that the necessary conditions are not met for the organisation of free, fair, transparent and credible elections... the AU Commission will not observe the local and parliamentary elections," AU chief Nkosazana Dlamini-Zuma said in a statement.
Almost four million are registered to vote, but the opposition are boycotting the polls, claiming it is not possible to hold a fair vote.
Election commission chief Pierre-Claver Ndayicariye said he had not received any official notification confirming the opposition withdrawal from the vote.
"This is nothing new in Burundi. In Africa, boycott is another way of doing politics," he said. The opposition boycotted polls in 2010.
Civil society groups backed the boycott in a joint statement calling on voters to skip the "sham elections" and urging the international community "not to recognise the validity" of the polls.
Under the constitution, based on peace deals that ended the civil war, there are strict ethnic quotas in parliament.
Parliament must be made up of 60 percent from the majority Hutu people -- who make up some 85% of the population -- with the remaining 40% of elected seats reserved for the minority Tutsi.
Many fear a repeat of that conflict, which split the country along ethnic lines, pitting the majority Hutus against the minority Tutsis.