Boko Haram gunmen killed nine Nigerian soldiers after launching an ambush on a military convoy in the troubled northeast, a local official and a hospital source told AFP Thursday.

The troops were responding to a distress call late Wednesday in the Madagali area of Adamawa state when they were bombarded by Islamist rebels armed with anti-aircraft weapons mounted on the backs of 4X4 trucks, said Maina Ularamu, a local government official in the area.

"There was heavy fighting yesterday evening between soldiers and Boko Haram gunmen," Ularamu said.

He added that the Islamists "ambushed a military convoy on a mission to avert a planned attack... on Izhe village."

Adamawa is one of three northeastern states which has been under emergency rule since May, when the military launched a major operation to crush the Islamist uprising.

A source at the Federal Medical centre in the state capital Yola told AFP the hospital "received nine bodies of military personnel on (Wednesday) night from Madagali district."

Ularamu said the fierce gun battle that followed the Boko Haram ambush caused "casualties on both sides" but could not provide figures.

The clash was the latest in Boko Haram's extremist insurgency which has caused thousands of deaths since 2009, especially in the northeast.

On Tuesday, in neighbouring Borno state, at least 43 people were killed in two separate attacks blamed on the Islamists.

The deadliest raid struck the town of Konduga, where scores of gunmen razed more than half the village, spraying gunfire on fleeing civilians and killing 39.

Boko Haram has said it is fighting to create a strict Islamic state in the mainly Muslim northern half of Nigeria, Africa's most populous country and top oil producer.