SAN FRANCISCO, March 23 (Xinhua) -- The U.S. Federal Bureau of Investigation (FBI) Friday identified the man who had crashed through a security gate at a Northern California air force base Wednesday as an immigrant with legal permanent residence.

The attacker, who was killed in the fiery crash, was identified as Hafiz Kazi, 51, who came from India and had been living in the United States as a legal permanent resident since 1993. Kazi was living in Sausalito in the San Francisco Bay Area in Northern California.

Investigators found five propane tanks, three plastic one-gallon gas cans, several lighters and three phones in the vehicle.

They said Kazi deliberately detonated the propane tanks and his vehicle exploded after crashing through the main gate at the Travis Air Force Base, creating a huge fireball.

There were no reports of any other casualties.

The FBI said it was yet not clear whether the attack was linked to terrorism.

"There was some information out there that there might be some jihadi-type videos, things like that," FBI special agent in charge Sean Ragan said, added that they have not found anything so far.

The air force base Friday tweeted that security forces have begun implementing additional security measures at the main and hospital gates.

The base, about 88 km northeast of San Francisco, is home to the largest wing of the U.S. Air Force's Air Mobility Command, the 60th Air Mobility Wing. It houses about 26,000 people, including over 7,000 personnel on active-duty.