The incident occurred early on Wednesday during a U.S. anti-terrorist operation near the police station. U.S. troops accidentally fired several shots at the station, and police returned fire, sparking the shootout.
The U.S. military said in a statement that a civilian was also killed in the firefight, and 13 people were injured. The police station building was severely damaged.
A special commission, comprising Afghan Interior Ministry officials and NATO representatives, has been sent to Qalat to investigate the incident.
Coalition forces in Afghanistan have been heavily criticized over civilian deaths during their operations, but President Hamid Karzai has said that friendly-fire incidents between security forces are an unavoidable part of war.
