MAIDUGURI, Nigeria (AP) — Police say five suicide bombers trying to infiltrate Nigeria's northeastern city of Maiduguri have died in explosions that killed at least three civilians.

Deputy Superintendent Victory Isuku says the two attacks Sunday night are blamed on Boko Haram Islamic extremists.

He says three men wearing vests with explosives approached a military checkpoint while shooting. He says one exploded, killing all three and a civilian self-defense fighter.

Two hours later, two female bombers blew up, killing themselves and two unidentified people.

Soldiers and civilians fighting alongside them have stopped many suicide bombers before they can reach heavily populated targets in recent months.

The attacks continue despite President Muhammadu Buhari's announcement last month that Boko Haram has been crushed after the military destroyed their last forest stronghold.