Boko Haram jihadists ambushed a military convoy in northeastern Nigeria, killing 13 soldiers and a policeman, the army said Wednesday.
But an officer, speaking on condition of anonymity, said the militants had overrun an army base, and put the death toll at 18.
An army statement said the attackers ambushed a military convoy late Monday on a highway linking Maiduguri, the capital of Borno state, with Damaturu in neighbouring Yobe state.
"Sadly, 13 military and a police personnel... Paid the supreme price while extricating themselves from the ambush," said the statement, signed by local military spokesman Colonel Onyema Nwachukwu.
The attack followed an attempted raid on a nearby military base along the highway in Kukareta village, 20 kilometres (12 miles) from Damaturu, Nwachukwu said.
That attack was "repelled" by troops who "engaged and overpowered the terrorists, killing several of them", Nwachukwu said, adding that a soldier was injured.