Kabul, Afghanistan ? An attacker blew himself up in a failed assault on coalition forces Sunday in volatile southern Afghanistan, while two U.S. helicopters made emergency landings during combat operations, officials said.

The attempted attack against the coalition forces occurred after their convoy passed through the former Taliban stronghold of Kandahar. Afghan Interior Ministry spokesman Yousuf Stanekzai said the explosives detonated when the attacker was hit by a motorcycle. The blast killed the attacker and motorcycle driver and wounded two other people, U.S. military and Afghan police officials said.

One of the wounded was a coalition soldier, who was treated for minor injuries and returned to duty, said Lt. Mike Cody, a coalition spokesman. Afghan state television reported that the convoy was Canadian.

Hours earlier, the U.S. military said five American troops and an Afghan soldier suffered relatively minor injuries when two helicopters made emergency landings during combat operations. All the injured were in stable condition, the military said.