Two U.S. helicopters made emergency landings during combat operations in Afghanistan on Sunday, injuring five American troops and an Afghan soldier, the U.S. military said.

The two Chinooks made emergency landings in separate areas in southern Afghanistan, the military said.

Five U.S. soldiers were injured in a landing north of Kandahar that seriously damaged the helicopter, the military said. A purported Taliban spokesman claimed insurgents shot down the craft. The injured soldiers were listed in stable condition at a military medical facility, the military said.

Also in Kandahar, a homicide bomber detonated explosives on a street, killing himself and a civilian and wounding two passers-by, a police official said.

The bombing took place on a main street after a U.S. military convoy had passed by, Kandahar deputy police chief Abdul Hungar said. He said it was possible the bomber was targeting the convoy.

A purported Taliban spokesman, Qari Mohammed Yousaf, claimed the Taliban had shot down the military helicopter north of Kandahar with a rocket, but also said that all aboard were killed. Yousaf often calls news organizations to claim responsibility for attacks, but the information is frequently exaggerated or untrue. His exact tie to the Taliban leadership is not clear.

The second helicopter made an emergency landing at a forward operating base in Uruzgan province earlier in the day, the military said. One Afghan National Army soldier was injured and taken to a nearby U.S. military treatment facility, where he was also reported in stable condition, it said.

The military said it was investigating the causes of the incidents. It said both helicopters were involved in combat operations "against enemy forces."