An incident this week at a U.S. Air Force base in Northern California -- in which a vehicle burst into flames after crashing through the main gate -- is being treated as "an act of terrorism," according to a report.

Authorities said a driver died, likely by igniting himself, after gaining “unauthorized access" to Travis Air Force Base in Solano County, about 55 miles northeast of San Francisco, on Wednesday night.

There was no further threat to the base, where approximately 7,000 active military members and 3,700 civilians live and work, Air Force officials said.

The FBI has also joined the investigation alongside base officials.

“The safety and welfare of our airmen, their families and our local community is our top priority,” Col. John Klein, commander of the 60th Air Mobility Wing at Travis, said in a news release.

“I am extremely proud of how our first responders quickly addressed the situation to keep Travis and the surrounding area out of harm’s way. We are fortunate to have enduring relationships with federal and local law enforcement, and will continue to work hand-in-hand with them through the investigative process.”

The vehicle was reportedly carrying propane tanks, and the driver is thought to have started the fire deliberately, is believed to have ignited himself, CBS News reported.

FBI spokeswoman Gina Swankie and Travis spokesman Airman Christian Conrad declined to elaborate on the matter or identify the driver.

The Associated Press contributed to this report.