An explosion ripped through a group of civilians and foreign troops in eastern Afghanistan Wednesday, killing four children and a policeman and wounding dozens of civilians and three US soldiers, officials said. The Afghan Interior Ministry said in a statement that the blast in Nangrahar province occurred when a passing police vehicle hit a mine. The ministry called it a terrorist act, implying the mine had been planted by insurgents. Buz Muhammad, the province's deputy public health chief, said four children were killed. He also told The Associated Press that 43 people, most of them children, were wounded. Ahmad Zia Abdulzai, the spokesman for the provincial governor, told the AP earlier that the wounded included three US soldiers. NATO's International Security Assistance Force said nine of its soldiers were wounded, but could not specify their nationalities. In a separate attack in the province, four Afghan policeman were killed when a remote-controlled bomb blew up their vehicle in the Khagyani district, Abdulzai said. Also Wednesday, at least 13 people were injured in an explosion at a market in Khost province in eastern Afghanistan. Meanwhile, Afghan security forces have captured a former local police chief who defected to the Taliban and fought for them wearing police uniform and using stolen weapons, an official said Wednesday. The renegade police officer, Muhammad Qasim, deserted his post as police chief of a violence-plagued district in southwestern Farah province early last year, taking with him some officers as well as uniforms, weapons and vehicles. He and his men joined militants to fight Afghan and Western forces in Bala Blok district, Farah's Deputy Governor Muhammad Younus Rasouli said.