Police and witnesses say at least four people have been killed in three attacks by suicide bombers in Nigeria's northeastern city of Maiduguri.

Borno state police commissioner Damian Chukwu says the first attack late Tuesday involved a male bomber who was shot dead by a military sniper after he was seen moving toward a security checkpoint.

Then two teenage female suicide bombers attacked early Wednesday.

Chukwu says the first was shot dead by soldiers and the second blew herself up after civilian self-defense fighters stopped her from moving toward a mosque. The bomber and one of the fighters were killed.

Maiduguri is the birthplace of the Boko Haram Islamic insurgency. It continues to carry out deadly attacks despite the recent claim by Nigeria's president that the movement had been crushed.

AP