KABUL, Afghanistan — A man driving a Toyota minivan laden with explosives steered into an American convoy on Tuesday morning, killing 18 people, including 5 American troops, and 12 civilians caught in rush hour traffic in the Afghan capital.

Forty-seven civilians were wounded, and a sixth soldier from another NATO country was also killed, officials said.

The blast scattered body parts for 200 feet as the wounded, many of them women and children, some without limbs, lay in the road moaning for help.