Burundi's government and opposition opened a new round of negotiations on Saturday as part of a last-ditch effort to resolve a major political crisis over President Pierre Nkurunziza's controversial re-election bid, a source close to the talks said.

Presidential elections are due to take place in the impoverished central African nation on Tuesday and the opposition has until now stood by its plans to boycott the polls, leaving little time for a deal to be reached.

The crisis in Burundi began in late April when Nkurunziza announced his intention to stand for a third consecutive five-year term, despite a constitutional two-term limit, sparking months of turmoil and a failed coup in mid-May.

Opposition groups say another term would violate a peace deal that paved the way to end a dozen years of civil war in 2006.

There are fears the current crisis could plunge the country, which has a history of ethnic and political violence, back into war -- adding another major crisis to the already unstable Great Lakes region.

A source close to the talks said both sides were currently discussing "security in the country and the return of refugees", with regional power Uganda acting as mediator. More than 150,000 people have fled the country because of the unrest, which has included a fierce government crackdown on demonstrations that has left at least 100 dead.

The two sides also plan to discuss the electoral calendar, with the opposition demanding that the results of last month's parliament elections be nullified.

Nkurunziza's ruling CNDD-FDD party scored a widely-expected landslide win in parliamentary polls held on May 29, but these were boycotted by the opposition and condemned internationally as neither free nor fair.

The government, however, has so far refused any further delay in the presidential elections, and an opposition source accused Nkurunziza of "trying to buy time".

Campaigning for the elections was due to officially end later on Saturday, and in one of his final campaign rallies on Friday the president promised the country "five more years of peace" if he is re-elected.

"If you choose the CNDD-FDD you are sure of five more years of peace," he told a gathering of at least 1,500 people.

Nkurunziza is almost assured of victory if the polls do go ahead on Tuesday, because of the opposition boycott.

The country has been left without most of its independent media outlets, after several radio stations were attacked and destroyed in fighting during the attempted coup.
Source: AFP