Suspected Boko Haram fighters ambushed a convoy carrying the head of the Nigerian army, the military said on Sunday, sparking a firefight in which 10 militants and a soldier were killed.

Lieutenant General Tukur Buratai, who was unharmed, was visiting troops in the northeast Saturday when insurgents attacked in Faljari village, 45 kilometres (28 miles) east of Borno State capital Maiduguri, army spokesman Sani Usman said in a statement.