A second top Burundian election official has reportedly fled to Rwanda in another blow to Burundian President Pierre Nkurunziza's controversial bid to stand for a third term in office.

Sources told the AFP news agency that the election commission's vice president, Spes Caritas Ndironkeye, jetted out of the crisis-hit central African nation on late Friday, leaving behind a resignation letter and preparations for next week's parliamentary elections in disarray.

An electoral commission source said Ndironkeye "left without saying goodbye, without saying where she was going," according to AFP. A second member of the five-person commission, Illuminata Ndabahagamye, is also thought to have fled, sources said.

"She fled the country with her daughter," a relative of Ndironkeye who did not wish to be identified told the Reuters news agency.

A spokesman for the electoral commission, known as CENI, Prosper Ntahorwamiye, said it had received similar information but had no evidence that Ndironkeye had fled the country.

"Technically, the Election Commission can continue to work with four out of five members. But if two have left, no decision can be taken and it will be impossible to replace them before June 5," a source told AFP.

Burundi's crisis surrounds Nkurunziza's bid to stands for a third consecutive five-year term in office, something that opposition and rights groups say move violates the constitution as well as the terms of a peace deal that ended a 13-year civil war in 2006. The political crisis is the biggest in the east African nation since its ethnically charged civil war ended.

Top judge flees

Hundreds of thousands of people were killed in the conflict, marked by massacres between the majority Hutu and minority Tutsi communities.

Asked to rule on the issue, Burundi's constitutional court found in favour of the president, but not before one of the judges also fled the country, claiming that its members were subject to death threats.

The capital Bujumbura has been hit by weeks of civil unrest that has left at least 30 people dead in a major security crackdown, and the crisis intensified earlier this month when a top general staged a failed coup attempt.

The Human Rights Watch, a US-based rights group, said Burundi has been gripped by "pervasive fear", while the International Crisis Group, a Belgium-based conflict-prevention think tank, said Burundi was headed back into conflict unless the president backed down.

On Thursday, the EU and Burundi's influential Roman Catholic Church pulled out from observing the elections, saying next month's vote could not be fair because of daily unrest and a crackdown on media, Reuters said.

Regional leaders from the East African Community common market will hold a summit in the Tanzanian capital on Sunday to discuss the crisis in Burundi.

Source: Agencies