Khan said armed men flattened the gate before dawn with a rocket-propelled grenade, fatally shot a guard and set fire to 106 vehicles, including about 70 Humvees.

An Associated Press reporter who visited the depot saw six rows of destroyed Humvees and military trucks packed close together, some on flatbed trailers, all of them gutted and twisted by the flames.

Khan said shipping documents showed they were destined for U.S. forces and the Western-trained Afghan National Army.

The attackers fled after a brief exchange of fire with police, who arrived about 40 minutes later, he said.

Nine other guards who stood helplessly aside during the attack put the number of assailants at 300, Khan said. Police official Kashif Alam said there were only 30.

It also dents faith in Pakistani authorities already under pressure from India and the U.S. to act on suspicion that the deadly terror attacks in Mumbai were orchestrated by Islamic extremists based in Pakistan.