KABUL, Afghanistan >> An Afghan driver somehow caught fire Wednesday when he crashed a stolen truck as U.S. Secretary of Defense Leon Panetta’s plane was landing nearby, officials said.

No one in Panetta’s party was hurt, said a Pentagon spokesman, Navy Capt. John Kirby.

In the bizarre incident, the pickup truck traveled at high speed and crashed into a ditch near the ramp where Panetta’s plane was going to park at the British airfield in Helmand province in southern Afghanistan.

Suddenly the driver caught on fire, but the truck did not explode, said Col. Gary Kolb, a U.S. military spokesman in Afghanistan, countering earlier reports that the vehicle burst into flames. The driver was treated for burns.

There was no indication that the driver knew that Panetta was in the plane. There were no explosives found either in the vehicle or on the driver, Kolb said. Panetta was told about the incident after he got off the aircraft.

It was unclear what the driver had in mind, or even if it was a failed attack. "It’s too early to say right now," Kolb said. "It may have been a coincidence."

He said a service member with the U.S.-led coalition saw the Afghan stealing the truck and tried to stop him, but the man hit the service member with the truck as he drove off. The service member was injured. Kolb did not say how seriously.

In Washington, British Prime Minister David Cameron said it was too early to know exactly what happened, but he stressed that security for troops was a priority.

"If there are things that need to be done in the coming hours and days to keep them safer, no doubt we will do them," Cameron said.

Cameron spoke during a joint news conference with President Barack Obama, who is hosting the British leader in Washington on an official visit.