Two suicide bombers struck a joint U.S.-Afghan military base in central Afghanistan early Saturday morning, killing 12 people, authorities said. The attack also wounded 57 others, said Shahidullah Shahid, a spokesman for the provincial governor. A majority of the casualties included civilians, but four Afghan police officers were among those killed, he said. One bomber attacked the base on foot, then another one detonated a truck, the spokesman was quoted as saying by CNN. No international coalition service members died in the attack in Sayedabad district, according to Maj. Adam Wojack, a spokesman for the International Security Assistance Force. The Taliban claimed responsibility for the attack.