Maiduguri, the capital of northern Borno state, lies in the heartland of an insurgency by Islamist militant group Boko Haram, and is often hit by bomb attacks. A Nigerian security source said the bomb went off at 12:15 p.m. (1115 GMT). The girl was killed and the bodies of at least 16 victims were counted in one hospital by mid-afternoon, civilian joint task force member Zakariya Mohammed told Reuters.

"Right now, there are 27 injured people in Borno Medical Hospital, while more were taken to other hospitals," he said.

The northeastern states of Borno, Yobe and Adamawa are bearing the brunt of a five-year-old insurgency by Boko Haram, which wants to revive a medieval caliphate in Nigeria, Africa's most populous country and its biggest energy producer.

Last year more than 10,000 people died in the violence, according to an estimate by the Council on Foreign Relations.

About 130 km (80 miles) away in the Yobe state capital Damaturu, the army subdued an Islamist militant attack on Friday evening, but not before militants had torched several buildings, a Reuters reporter in the city and witnesses said.

The Reuters witness saw a number of burnt buildings, including a police station and a mosque in the Abacha market, along with several shops.

Defence spokesman Major General Chris Olukolade said that five soldiers were wounded defending the city and the number of civilian casualties was still being determined.

Damaturu was last attacked in early December when air strikes called in to halt advancing militants.

READ MORE HERE