BUJUMBURA, Burundi -- Seven more people were killed in Burundi's capital in violence associated with turmoil over President Pierre Nkurunziza's extension of his term in office, witnesses said Wednesday.

The international community has warned that the central African country could slide into chaos if the killings continue. The UN says at least 240 people have been killed since April when Nkurunziza's candidacy was announced.

Men in police uniforms pulled five people from their houses in Cibitoke neighbourhood and shot them dead Wednesday morning, resident Salima Bukuru said. Their bodies were left on the roadside, she said.

"That one works for a company which processes soap. He had just returned home from the night shift when they came for him. They beat him as they pulled him out of the house," Bukuru said pointing at a body among the group of five bloody corpses on the side of the street in Cibitoke.

"I asked why they were beating him and they started to beat me," she said.

Rights activist Vital Nshimiyimana said some of the five murdered had just been released from prison where they had been held for months after being arrested for protesting against Nkurunziza's third term in office.

"The killings were predetermined by the police," Nshimiyimana said.

About 100 people who opposed Nkurunziza's bid to extend his tenure were released Tuesday.

Another person was shot dead in the afternoon in the Jabe neighbourhood, while another was killed in Bwiza by people in police uniform on Tuesday night.

Nkurunziza took power in 2005 near the end of a civil war in which some 300,000 people died. This year Burundi has been unsettled by months of violent street protests following the announcement in April that Nkurunziza would seek a third term. The unrest boiled over into a failed coup in May. Nkurunziza was re-elected in July.

There is a serious risk that if the violence in Burundi isn't stopped there could be a civil war -- and after that, "everything is possible," the UN special adviser on the prevention of genocide said Tuesday.

"I would not say that tomorrow there will be a genocide in Burundi," said Adama Dieng. "But there is a serious risk that if we do not stop the ongoing violence, this may end with a civil war and following such civil war everything is possible."

Ssuuna contributed to this report from Kigali, Rwanda. AP writer Edith M. Lederer contributed from the United Nations.