Two female suicide bombers blew themselves up in a crowded textile market in north Nigeria's biggest city on Wednesday, killing at least four, police said.

Kano state police commissioner Adenrele Shinaba said the blast at the Kantin Kwari market in Kano city was "a twin suicide bombing carried out by two young girls in hijab".

"They came by the market and asked to be directed to a public convenience. The bombs detonated, killing them and four others," he told AFP. At least seven others were injured, he added.