The blast, destroyed the car in which the six men were sitting in, according to government officials.
"Altogether six people were killed. We believe Dr. Jalal, head of the Defence Minister's personal security was killed when the terrorist that was caught set off explosive devices he had attached to his body," said a Defence Ministry spokesman.
Kabul's deputy police chief Mutahullah Rahmani told news agencies the explosion occurred to the west of the Airport.
"Two of the dead bodies have military uniforms and two others are wearing civilian clothes," he said. "We are investigating."
Car in flames
Gul Nabi Ahmadzai, chief of staff at the interior minister's office, told AFP the car was a Toyota pick-up truck.
Ahmadzai was at the scene of the explosion but had no further details.
Witnesses could see a car in flames close to the airport, but security forces prevented people approaching it. Peacekeeping International Security Assistance Force troops were seen at the site around 200 meters from the airport.