The Taliban bomber detonated his deadly ordinance in an attempt to breach the outer security perimeter of Kandahar airfield, killing two Afghan civilians and wounding 14, according to the Associated Press.
Officials from the International Security Assistance Force could not comment on any U.S. or allied casualties as a result of the bombing. Panetta was in no immediate danger as a result of the bombing, the AP reports.
Panetta reportedly just left Kandahar airfield for a meeting with Afghan president Hamid Karzai in Kabul at the time of the attack. He had been meeting with top U.S. commanders in southern Afghanistan and elsewhere in the country to discuss details of the Pentagon's withdrawal strategy.
The Obama administration is planning to have all U.S. combat troops out of the country by 2014. More than 33,000 American soldiers, sailors, Airmen and Marines left Afghanistan this summer.
Gen. John Allen, the top U.S. commander in Afghanistan, is reportedly finalizing his recommendations for how to pull out the remaining 68,000 personnel in the country.
Thursday's assault was the second time this year an attempted attack on U.S. facilities in Afghanistan has taken place either during or shortly after a Panetta visit.
In March, the DOD chief was arriving at Camp Leatherneck, the Marine Corps' main base in southern Afghanistan, for an unscheduled visit when an Afghan employee at the base attempted to run down Panetta's welcome delegation in a stolen white Hilux sport utility vehicle belonging to British forces.
The truck ran onto the airfield as Panetta's plane was taxiing in and missed the delegation, bursting into flames after crashing into a nearby barrier. The attacker died shortly thereafter from severe burns suffered during the attempted attack, according to ISAF.
A subsequent investigation into the attack cleared the father and the brother of the attacker, who was working as an interpreter at the base in Afghanistan's restive Helmand Province where the attack took place.