Gunmen executed nine people in Burundi's capital hours before police launched house-to-house searches for weapons on Sunday, amid international fears of fresh bloodletting in the central African nation. Hundreds of police and soldiers ringed the opposition flashpoint Mutakura district of the capital Bujumbura early Sunday to start a widely feared crackdown on "enemies of the nation."
Residents said security forces carried out house-to-house searches.
City mayor Freddy Mbonimpa said police were searching for "hidden weapons," insisting the raids were being "done professionally, because the police are using weapon detectors."
The mayor said seven people were killed in an "execution" attack on a bar on Saturday night, adding that a probe had been launched to track the "assassins." Two others later died of their wounds.
Witnesses said attackers stormed into the bar, forcing those drinking outside to enter and lie on the ground before opening fire.
International alarm has grown as a government amnesty to hand in weapons ended with fears that it will trigger further violence, drawing warnings from the head of the UN, Washington and the world's only permanent war crimes court.
Police later displayed around a dozen rifles and grenades they said had been seized in the raids, which officials said would continue in coming days.
Rwandan President Paul Kagame has accused Burundi's leaders of carrying out "massacres" on their people in his most critical speech yet of the crisis in the troubled neighbouring state.
"People die every day, corpses litter the streets... How can the leaders allow their population to be massacred from morning to night?" Kagame said, speaking in Kinyarwanda on Friday.
Relations between Rwanda and Burundi are tense, with Bujumbura accusing Kigali of backing those who oppose President Pierre Nkurunziza's controversial third term in office.