A "complex" ambush involving a suicide car bomb and militant gunfire killed 16 Afghan civilians and wounded 25 people during an attack on a coalition convoy in eastern Afghanistan on Sunday, officials said.
The suicide bomber hit the American convoy with an explosives-packed minivan, said Noor Agha Zawok, the spokesman for the governor of Nangarhar province.
Militants then fired gunfire from several directions and coalition forces returned fire, the US military said.
Hundreds of Afghans gathered to protest the violence, blocking the road and throwing rocks at police, with some demonstrators shouting "Death to America! Death to Karzai," a reference to President Hamid Karzai.