Nigerian officials say 16 Boko Haram extremists and two soldiers have been killed when the extremists tried to ride explosives-laden motorcycles into an army base in the country’s volatile northeast.

An army spokesman, Col. Sani Kukasheka, said in a statement Saturday that soldiers at the base in Rann in Borno State repelled the extremists with a gunfight that went on for hours.

He said two soldiers were killed when a suicide bomber drove into a truck and exploded.

Kukasheka said soldiers found most of the bodies of the attackers Saturday morning, but he added that “quite a number escaped with gunshot wounds.”

Boko Haram’s nearly seven-year-old insurgency has killed some 20,000 people and forced 2 million from their homes. The Nigeria-based group last year began regular attacks in neighboring countries.