Anti-government gunmen attacked military sites in Burundi's capital on Friday and up to seven people were killed in fighting, officials and soldiers said, the latest flare-up in a nation Western powers fear is sliding back into ethnic conflict. Two soldiers and five attackers were killed in clashes around a base in Ngagara, a district of Bujumbura, one soldier told Reuters. He lives outside the base, one of three sites attacked in the capital, but said he spoke to colleagues inside. A military spokesman could not be reached for comment. Heavy gunfire and blasts erupted in the early hours of Friday morning and shots were still heard across the capital after daybreak. Residents said the streets were empty when people normally headed to work and police were out in force. The violence in Burundi is unnerving for a volatile region which only two decades ago saw a genocide in next-door Rwanda. Night-time gunfire and sporadic blasts have been common in Bujumbura during a crisis sparked in April by President Pierre Nkurunziza's bid for a third term, which opponents, often called 'Sindumuja', said violated a deal that ended civil war in 2005. Nkurunziza won a disputed election in July. The crisis led to a failed coup in May. One of the generals behind that coup said in July the group still sought to topple the president, raising worries that the poor nation was slipping into conflict again. Other plotters were caught and face trial. "Sindumuja tried to attack military camps but they failed," presidential media adviser Willy Niyamitwe wrote on Twitter, describing the raids as "a diversion" to try to free prisoners. Without mentioning any casualties, he dismissed comments that the city was empty, saying it was "business as usual" with people at work and children at school. A deputy presidential spokesman said on his Twitter account that a cabinet meeting was taking place in the morning. He also said the aim of the "armed gang" was to free prisoners. Alongside the raid on Ngagara camp in the north of Bujumbura, two southern sites were attacked, namely Muha camp and ISCAM, a higher institute for officers, soldiers and residents said. Till now, battle lines in Burundi's crisis have followed the political divide, but Western powers and regional nations fear old ethnic rifts could reopen if violence continues unchecked. Burundi's 12-year civil war had pitted rebel groups of the Hutu majority, including one led by Nkurunziza, against what was then an army led by the Tutsi minority. Rwanda has the same ethnic mix.