BUJUMBURA, Burundi (AP) -- At least four people were killed in overnight violence in the Burundi capital, the police said Sunday as sporadic gunfire and loud explosions continued to echo across the city.
A local human rights activist, however, said up to seven dead bodies had been discovered and blamed the police for the killings.
Bujumbura has been wracked by violence since April when the president announced he would seek a third term, sparking violent street clashes and a failed coup attempt.
Opponents and supporters of the president appear to be targeting each other in revenge attacks, raising fears of a possible return to civil war.
Deputy Police Spokesman Moise Nkurunziza said that three of the victims died in the northern neighborhood of Ngagara, while a fourth was killed in the southern neighborhood of Kanyosha. At least 28 people were arrested overnight, he said.
But Anschaire Nikoyagize, the president of the Burundian League for Human Rights, told The Associated Press that seven people had been killed overnight in confrontations with the police, with some tortured and beheaded.
"Relatives of the victims told us those who were killed were thought to be connected to people opposing (the president's) third term," Nikoyagize said, adding that shootings and explosions were still going on in Bujumbura Sunday afternoon.
A military official, speaking on the condition of anonymity because he was not authorized to speak to a reporter, said there was an explosion inside the water and electricity company.
The U.N. has cited at least 240 deaths since April, but the real toll is likely much higher.
Burundi also has a history of deadly conflicts between the country's Hutu and Tutsi ethnic groups.
Nkurunziza took power in 2005 near the end of a civil war in which some 300,000 people were killed between 1993 and 2006.