MAIDUGURI, Nigeria (AP) — Suspected members of the Boko Haram radical Islamist sect have killed seven people in two separate attacks in Nigeria’s north, authorities said Tuesday.

Adamawa State police spokesman Daniel Altine said attackers shot dead a policeman, a soldier and three bystanders Monday evening at a checkpoint in the town of Mubi. The attackers may have been avenging the army’s killing of six suspected Boko Haram members at a training camp in the town on Monday, Altine said.

Meanwhile, army spokesman Lt. Ikedichi Iweha said suspected sect members shot dead two more policemen in the major northern city of Kano on Tuesday. He said soldiers killed one of the assailants during the attack.

Boko Haram has been accused of killing more than 340 people in Nigeria this year alone. The group has engaged in an increasingly bloody campaign to destabilize Nigeria’s weak central government.