BUJUMBURA, Burundi (AP) — At least six people in Burundi were killed in a gun attack believed to have been by rebels opposed to President Pierre Nkurunziza, an official said Tuesday, as unrest continued in the central African nation.

Many others were injured in the attack Monday night in Gisuru, Ruyigi province, near the border with Tanzania, Gisuru mayor Aloys Ngenzirabona told The Associated Press by phone.

Gisuru resident Abdul Komezamahoro said seven gunmen ran through a market, firing randomly before fleeing.

The attackers are believed to be connected to a group of exiles in Tanzania led by Leonidas Hatungimana, a former presidential spokesman who was sacked last year after he advised Nkurunziza not to seek a third term.

Five individuals suspected to have collaborated with the assailants have been arrested, said Eduard Mukoko, the police chief in Ruyigi. He gave no more details.

Nkurunziza's controversial decision to seek a third term — which he eventually won in July elections that the international community said lacked credibility — set off rounds of political violence in which more than 400 people have died.

Human rights groups blame Burundi's security forces for most of the killings, although rebel forces opposed to Nkurunziza are believed to have carried out attacks on government officials, including senior military officials.

Ssuuna reported from Kigali, Rwanda.