Three militants were killed on Thursday in suicide blasts during a raid in Bangladesh's Chittagong city, a police officer said.

"Two militants detonated themselves despite repeated requests to surrender," the officer told Xinhua news agency.

The third militant, a woman, succumbed to her injuries at a hospital.

Sounds of explosions and gunfire were heard from the militants' hideout at about 6 am.

The militants were suspected to be members of the Jamaatul Mujahideen Bangladesh extremist group.