Updated at 3:16 p.m. ET
(CBS/AP) A stolen vehicle breached a British airfield in Afghanistan where Defense Secretary Leon Panetta landed Wednesday. The Pentagon chief was unharmed.
Pentagon spokesman Capt. John Kirby told CBS News national security correspondent David Martin that the vehicle sped on the runway at Camp Bastion at "roughly" the same time Panetta's plane was landing.
The vehicle went into a ditch, where the driver, an Afghan civilian man, emerged from it on fire, Kirby said, correcting earlier comments in which he said the vehicle caught on fire. The truck did not catch fire. Kirby had no explanation for how the driver caught on fire.
No explosives were found in the vehicle or on the driver, who was not armed. He's being treated for burns at a hospital.
The Afghan stole the vehicle, a pickup truck, by pulling a NATO servicemember from it, Kirby said. The pickup hit the soldier, injuring him, as the driver sped to the ramp where Panetta's plane was scheduled to park.
It wasn't clear whether it was an attempt to attack the defense chief, whose travel to southern Afghanistan was not made public before he arrived. Panetta was informed of the incident after landing.
"We will not allow individual incidents to undermine our resolve to that mission," he told about 200 Marines at Camp Leatherneck. "We will be tested we will be challenged, we'll be challenged by our enemy, we'll be challenged by ourselves, we'll be challenged by the hell of war itself. But none of that, none of that, must ever deter us from the mission that we must achieve."
The incident is under investigation, according to NATO forces in Afghanistan.
Panetta's trip to the warfront, which included three stops in the south, was planned months ago, long before the weekend shooting spree allegedly by a U.S. soldier that claimed the lives of 16 villagers, including women and children.
Everywhere he went, including a meeting with provincial leaders, Panetta referred obliquely to the massacre, but didn't go into it in detail. Instead, he talked about the need for the Afghan and coalition forces to keep working together to help transition security of the country to the Afghan forces.
The trip, however, has propelled Panetta into the center of escalating anti-American anger in Afghanistan, with the shooting spree coming on the heels of the burning of Korans and other religious materials at a U.S. base. U.S. officials have said the incident was a mistake.
Maj. Gen. Mark Gurganus, the new Marine commander at Leatherneck, told reporters he has seen little backlash in his region over the shooting incident, and saw only a few protests of the Koran burning.
Panetta and other U.S. officials say the shooting spree should not derail the U.S. and NATO strategy of a gradual withdrawal of troops by the end of 2014. But it has further soured relations with war-weary Afghans, jeopardizing the U.S. strategy of working closely with Afghan forces on the transition.
There were clear concerns about security in the large tent at Camp Leatherneck, where Panetta was slated to talk to troops.
Before Panetta came into the hall, Sgt. Maj. Brandon Hall told the more than 200 Marines in the room to take their weapons outside and leave them there. Afghan troops had already been told not to bring their guns in.
"Something has come to light," Hall told the troops. It was a highly unusual order, and some in the audience said they had never seen that happen before.
Asked about the order, Hall said all he knew was that "I was told to get the weapons out."
A U.S. defense official said the request was not a reaction to an immediate threat. Speaking on condition of anonymity to describe security procedures, the official said the base commander made the decision that no one would be allowed to bring in weapons.
The official said the decision was made out of respect for troops from other countries, such as the Afghans, who are never allowed to bring guns into an event. It was not a request from Panetta or his security team, the official said.
Panetta met with several Afghan provincial leaders, and told them the primary mission is to prepare for the transition to Afghan security control.
He acknowledged there will continue to be challenges from the enemy as well as issues between U.S. and Afghan allies, but said everyone must remain committed.
The military has detained an Army staff sergeant in connection with Sunday's massacre. An Afghan official said Tuesday that surveillance video showed the sergeant walking up to his base and raising his arms in surrender.
The official, who spoke anonymously to discuss a private briefing, said U.S. authorities showed Afghan authorities the surveillance video to prove that only one perpetrator was involved in the Sunday shootings.