Gunfire, heavy artillery heard near Nigeria's Damaturu - Reuters witness
No further details were immediately available.
Suspected Boko Haram militants raided Damaturu, the capital of Yobe state and 130 km (80 miles) from the Islamist fighters' stronghold in Maiduguri, in early December. The military used ground and air forces to repel them.
(Reporting by Joe Hemba; Writing by Julia Payne; Editing by Louise Ireland)