Nigerian ground forces backed by warplanes on Tuesday battled Islamist Boko Haram militants in a second day of heavy fighting around a northeast town, in which the officer son of former President Olusegun Obasanjo was wounded, a senior official said.

Since the weekend, the government of Africa's biggest economy has sent in reinforcements to check a push southward into northern Adamawa state by Boko Haram, which has seized towns and territory in the northeast in recent weeks.

Nigerian air force jets were bombarding the Islamist group's positions in and around the town of Michika, the government official, who asked not to be named, told Reuters. They were also hitting the militants at Madagali, Bazza and Uba.