Chadian ground troops aided by a warplane have driven Boko Haram fighters from a Nigerian border town, witnesses have said.

Thursday's fighting marked the first such action by foreign troops on Nigerian soil to fight the armed group.

Resident Abari Modu said he witnessed the Chadian offensive on Malam Fatori village in Nigeria's Borno state.

"We saw the fighter jet when it started shelling and bombarding the insurgents who were lodging mostly inside the local government secretariat and the district head's palace," he told The Associated Press.

He said the bodies of many Boko Haram fighters were still in the town on Friday morning. He said the Chadian jet had pursued fleeing fighters to the border, and that the bombardment was coordinated with Chadian ground troops, offering the fighters no escape.

An unnamed Nigerian military officer confirmed the account to AP. There was no immediate official statement from Nigerian authorities about the Chadian offensive.

The offensive comes less than a week since Chad sent hundreds of troops into Cameroon, where they have set up a base to launch attacks against the armed group.

Boko Haram's five-year uprising has killed about 10,000 people in the last year and displaced at least one million people.

The African Union chairwoman, at an AU summit in Ethiopia, called for deployment of 7,500 African troops to fight the group.

The United States has also said that it would assist the fight against Boko Haram with technical support, training and equipment.