A suicide bomb blast outside a mosque and rocket-propelled grenades that exploded into homes as people slept killed at least 30 people in the Nigerian city of Maiduguri on Saturday, residents and officials said.

The explosion killed people who were prostrating themselves for afternoon prayers outside the mosque, including traders from a crowded marketplace in the largest city in Nigeria's troubled northeast, survivors said.

Trader Ali Bakomi said the bomber was pushing a wheelbarrow and pretending to be an itinerant trader.