Rival groups of soldiers continued to fight each other in Burundi's capital Bujumbura this morning, amid confusion over the success of an attempted coup against the president.

Gunfire and explosions were heard near state radio and television overnight, according to agencies.

The army chief of staff says the coup by a former intelligence head has failed. But President Pierre Nkurunziza has been unable to return from Tanzania, where he had gone to attend a meeting by regional heads of state.

His whereabouts are unknown.

The unrest began about a month ago, when Nkurunziza announced he was seeking a third term.

Opponents say the bid contravenes the constitution. Nkurunziza came to power in 2005.

The coup was announced on Wednesday by Maj Gen Godefroid Niyombare, a former intelligence chief and ally of the president, after Nkurunziza left for regional talks in Tanzania on Wednesday.

"The masses vigorously and tenaciously reject President Nkurunziza's third-term mandate. President Pierre Nkurunziza has been relieved of his duties. The government is overthrown," he said in a radio broadcast.

Thousands of people took to the streets to celebrate the announcement, marching on the centre of the capital, Bujumbura, alongside soldiers and two tanks.

Overnight, army chief of staff Gen Prime Niyongabo - a supporter of the president - announced: "The attempted coup... has been stopped."

His comments came after holding a night of negotiations with the defence minister, who backs the coup.But there appears to be little sign of any agreement within the armed forces itself.

Factions loyal to each side reportedly began fighting each other for control of the national television and radio station.

The scenes of joy in the streets on Wednesday have been replaced by an uneasy silence, interrupted by sporadic gunfire. The streets of Bujumbura are deserted. It has been an anxious night.

People have their ears stuck to their radio sets, listening to the only two private broadcasters still running. One of the two was attacked overnight. The popular RPA - Radio Publique Africaine, which broadcast an interview with Gen Niyombare on Wednesday - was also targeted and had to shut down.

The usually vibrant private media play a key role in shaping opinion here, and President Nkurunziza's supporters have been targeting them since the beginning of the crisis.

A lot of the tension overnight was also concentrated around the national broadcaster, which is strategic because it is the only outlet still broadcasting outside the capital.

US calls for normalcyA statement released by the US state department reiterated an earlier call for normalcy in Burundi following the coup talks.

"We support East African Community leaders’ call today for peaceful, democratic elections in line with Burundi’s electoral laws and the spirit of the Arusha Agreement,” reads part of the statement released yesterday.