His target was believed to have been the most senior Muslim leader in Borno, Alhaji Abubakar Umar Garbai El-Kanemi.

BBC: Boko Haram timeline: From preachers to slave raiders

He spoke haltingly to Borno state Gov. Kashim Shettima in the Kanuri language of Nigeria's northeast, surrounded by still-frightened villagers.

NPR: Officials: At Least 185 Killed In Nigeria Attack

Spokesman Lt Col Sagir Musa said the "fortified" camps were in a forest and a game reserve in Borno State.

BBC: Boko Haram crisis: Nigeria raids 'kill 17 militants'

The BBC has also received reports of civilians fleeing remote areas in Borno State and arriving in towns on the border with Cameroon.

BBC: Nigeria army's offensive to continue 'as long as it takes'

Last week, President Goodluck Jonathan declared a state of emergency in three north-eastern states - Borno, Adamawa, and Yobe - after a series of deadly attacks by militant groups.

BBC: Nigeria: Boko Haram in disarray, says army

The BBC's Tomi Oladipo in Lagos says President Jonathan wants to use his trip to the states of Borno and Yobe to assert his authority in the face of the growth security threat.

BBC: Nigeria's president rejects Boko Haram amnesty call

In July and August 2012 suicide bombers tried but failed to kill the shehu - or traditional ruler - of the Borno emirate in north-east Nigeria as well as the emir of Fika in Yobe state.

BBC: Nigeria: Kano reels after emir attack