Kabul - A suicide car bomb attack outside the main US base in Afghanistan on Wednesday injured three civilians, the military said in a statement.

The attack took place near an entry checkpoint of Bagram airfield, north of Kabul city, the biggest US military base in the country, wounding three civilian contractors, the US military said in statement, but did not disclose the nationalities of the victims.

"The driver, who was carrying explosives, abandoned the vehicle before it detonated. The explosive he was carrying detonated as he ran away from the vehicle," it said, adding, "The attacker was killed in the second explosion."

It said no military personnel were hurt in the blast and it was not clear if any additional personnel were in the vehicle.

The wounded contractors were evacuated to a hospital inside the military base. (dpa)