At least four people were killed when Boko Haram fighters opened fire on a military convoy transporting civilians and food aid in northeastern Nigeria, security sources said Sunday.
Troops later killed two jihadists and recovered weapons after trailing them to nearby villages, the sources said.
"We've been informed that Boko Haram terrorists killed four people in an ambush against a civilian convoy near Gamboru," on the border with Cameroon late Saturday, Babakura Kolo, a member of a paramilitary force battling the jihadists, told AFP.
The attackers arrived in two pick-up trucks before opening fire on the vehicles.
They also managed to steal a lorry carrying food aid to thousands of people displaced by violence in Gamboru, as well as two other vehicles, a local witness said.
Boko Haram has carried out a string of suicide attacks and kidnappings in northeastern Nigeria, in recent years, particularly in Borno state, leaving at least 20,000 people dead and displacing 2.6 million since 2009.
The strategic 140-kilometre (85-mile) trade route linking the Borno state capital Maiduguri to Gamboru was reopened in July last year after it was shut by the military for two years due to incessant jihadist attacks.
Trucks carrying goods and passenger vehicles use the road under military escort but food-starved fighters still launch sporadic ambushes on convoys from their hideouts.