By Clement Manirabarusha
BUJUMBURA, June 29 (Reuters) - Burundians voted for a new parliament on Monday after a night of sporadic blasts and gunshots and weeks of violent protests against President Pierre Nkurunziza's attempt to win a third term in office.
Voting appeared slow in several districts for an election boycotted by the opposition and condemned by African and European nations as lacking the conditions to ensure it was fair.
"We don't see many people," one diplomat said.
The European Union, a major donor, threatened on Monday to withhold more funds to the aid-reliant nation after Burundi ignored U.N. and African calls for a postponement of the parliamentary vote and a presidential election on July 15.
Opponents say the president's bid to stand again violates the constitution. But the government has pressed on with the election schedule while the country goes through its worst political crisis since an ethnically-charged civil war ended in 2005.
Aimable Niyonkuru, 20, once a supporter of Nkurunziza's CNDD-FDD party, said he would not vote because the president had not improved the economy or delivered on other promises.
"I am really disappointed about what all politicians are doing," he said.
Dozens of people queued at a polling station in one Bujumbura district. But in areas that have seen the most unrest against the president, there was little sign of an election.
Nkurunziza, a rebel commander-turned-president who has built a powerbase mostly in rural areas with a down-to-earth style, cycled from his village in north Burundi to vote at a nearby polling station, one witness said.
Almost 140,000 people, or more than 1 percent of the 10 million population, have fled across the country's borders, causing concern in a region with a history of ethnic conflict, particularly in neighboring Rwanda which saw genocide in 1994.
A presidential spokesman said voting was proceeding smoothly and African and European states could not judge the process before it was completed. He said any further delay in the votes was "out of the question."
The president cites a court ruling saying he is permitted to run for a third term and has refused to back down. Dozens have died in the unrest since he said in April he would run again.
Sounds of shooting and at least two explosions were heard overnight in the capital Bujumbura. A witness reported another blast in Bujumbura's Musaga district on Monday morning.
The private Iwacu newspaper website cited police saying two grenades exploded in Mayuyu district 25 km (15 miles) southeast of the capital. A police spokesman could not be reached for comment.
A spate of such attacks in recent days has killed four people and wounded dozens.
The European Union said Burundi's decision to ignore U.N. and other international demands to delay voting further was a "serious matter" and could lead to more aid being withheld.
The EU, European nations and the United States have already halted some funds, including support for the elections. European states together fund about half Burundi's annual budget.
"The organization of legislative elections on June 29 without establishing the minimum requirements to ensure their credibility, transparency and inclusiveness, can only exacerbate the deep crisis in Burundi," the European Union said.
The African Union said on Sunday it would not send observers as it did not believe voting would be fair. The European Union also said it was withdrawing its observers.
"Not being there means they are playing the game of the radical opposition who have boycotted the process," presidential spokesman Gervais Abayeho said, adding U.N. observers were still monitoring the vote.
Critics have said basic requirements for a fair poll mean ensuring the media operates freely and that the ruling party's Imbonerakure youth wing and other groups are disarmed. The CNDD-FDD dismisses charges its youths are armed.
(Additional reporting by Adrian Croft in Brussels and Tom Miles in Geneva; Writing by Edmund Blair; Editing by Andrew Roche)