KABUL, Afghanistan — Taliban suicide bombers attacked a joint U.S.-Afghan air base in eastern Afghanistan early Sunday, detonating explosives at the gate and sparking a gunbattle that lasted at least two hours with American helicopters firing down at militants before the attackers were defeated.

The attackers and at least five Afghans were killed, officials said. Taliban spokesman Zabiullah Mujahid claimed responsibility for the attack.

It was the largest clash at the Jalalabad air base since February, when a suicide car bombing at the gate triggered an explosion that killed nine Afghans, six of them civilians.