An explosion in the Nigerian city of Yola has caused multiple deaths and injuries, with some reports saying more than 30 people may have died.

The blast appears to have struck a busy market area where traders were closing up for the day.

Nigerian President Muhammadu Buhari visited Yola on Saturday, declaring that the Islamist militant movement Boko Haram was close to defeat.

Yola has twice been hit by deadly bomb attacks this year.

The city lies in the northern state of Adamawa, one of the worst hit by the Boko Haram insurgency.