Updated

Officials say a bomb exploded near a drinking spot in the northeastern Nigerian town of Mubi, apparently causing multiple casualties.

The explosion Sunday evening came less than 48 hours after a letter purportedly from the Boko Haram terrorist group threatened to attack a university in the town.

A local official, Ahmad Gude, says security personnel were taking victims to the hospital, but he did not have an exact casualty figure.

A resident, David Dauda, says the blast went off as people were leaving a football match nearby and he saw more than 30 bodies in the area.

Mubi is in Adamawa state, one of three northern Nigerian states under a year-old emergency rule imposed by President Goodluck Jonathan to fight Boko Haram, which seeks to impose Islamic rule in Nigeria.