He was driving at least 50 mph, according to the Alameda County Sheriff's Office.
Authorities said the man jumped out of his truck and fled on foot. They believe he may have jumped into the San Francisco Bay surrounding the airport because a police K9 tracking his scent followed it to the edge of the water and stopped.
The search continues for a man who rammed through a gate at Oakland’s Int. airport & onto the tarmac, according to Alameda County deputies.— Luz Peña (@LuzPenaABC7) September 2, 2019
“...we can’t draw nexus to a terrorist event. It is still obviously very suspicious,” said Sgt. Kelly.
Sgt. Ray Kelly with the Alameda County Sheriff Department said the suspect was seen driving around the terminals prior to the incident.
"At this point, we can't draw a nexus to a terrorist event. It is still obviously very suspicious this gentleman's behavior," said Kelly.
His truck was also abandoned on the road next to the water and later towed away. Inside his truck, authorities found Airsoft replica weapons and a mask.
"Initially we looked into the vehicle and had to secure the vehicle. On first glance, we saw what it looked like a cache of weapons. Looked like assault rifles and various paraphernalia with hoods and masks," Kelly said. "They turned out to be airsoft weapons."
Police can't say if terrorism was a possible motive.
The Sheriff's Department says it is not likely that the suspect survived after entering the water.
"The survivability as time has gone by is not good," said Kelly. "The water is very cold."
His name was not released, but he is believed to be a resident of Santa Cruz County.
There is was never a threat to planes or passengers, as he was driving on inactive tarmacs. However, for more than an hour, flights were diverted onto the airport's north field.
The sheriff's department says security measures at the airport will be reviewed.
Keonnis Taylor, spokesperson for the Oakland International Airport, said they're investigating the incident and added, "All details are referred to law enforcement. The airport will not discuss details regarding its security program."
Sgt. Kelly confirmed they'll be working with the FBI and federal partners to figure out what the suspect's intentions were and why he was around the area prior to the incident.
Active search underway @IFlyOAKland after a suspect fled from deputies and rammed a gate onto the airport tarmac. Suspect fled on foot and may have jumped into the water surrounding airport. @oaklandpoliceca @CHP_GoldenGate assisting with search. No active threat to air traffic.— Alameda County Sheriff (@ACSOSheriffs) September 1, 2019
Stay with ABC7 News for the latest details on this developing story.