Nairobi (AFP) - At least seven people have been killed within 24 hours in Burundi in gun battles and grenade blasts with bodies found dumped on the streets, local officials and witnesses said Wednesday.

Gunmen also ambushed a police patrol, the latest violence in now near daily attacks.

Two people were killed and six wounded in a grenade blast in a bar in Mutimbuzi, some 10 kilometres (six miles) east of the capital Bujumbura, on Tuesday night, senior local official Damien Barindambi said.

Another grenade attack, in Mugongo Manga, some 30 kilometres east of the capital, wounded three people shortly after, officials there said.

Meanwhile in Bujumbura, the bodies of three youths were found early Wednesday on the streets of the city's Mutakura district, witnesses said, adding that with no blood seen, the corpses were likely dumped overnight. Another was found elsewhere in the city.

Police spokesman Pierre Nkurikiye said a policeman was killed and three wounded by "terrorists" who hurled grenades before opening fire on the patrol on Tuesday night.

Burundi's government blames a string of attacks on "armed criminals", but the UN has warned that Burundi risks sliding back into civil war after a dramatic rise in violence.

President Pierre Nkurunziza, an ex-rebel turned born-again Christian who believes he has divine backing to rule, won a third term in power in July, despite concerns over the legality of him serving a third consecutive mandate.

UN observers said the polls were neither credible nor free. Since the elections, clashes between gunmen and the security forces have become a near daily event.