(CNN) -- A U.S. Marine shot and killed a uniformed Afghan police officer after a dispute Saturday, NATO said, prompting an investigation by the alliance's International Security Assistance Force.
According to initial reporting, the police officer and the Marine had an argument while conducting security operations Saturday at a patrol base in Helmand province, in the southern part of the country, ISAF said in a statement.
"After the dispute, the uniformed police officer was reportedly making threatening statements and handling his weapon carelessly," ISAF said.
The Marine reported the behavior to his chain of command, the statement said.
"After departing his post, the uniformed police member returned with his weapon raised and pointed toward the Marine," the statement said. "The Marine responded with escalation of force procedures, including shouting at the individual to put the weapon down."
"The individual failed to comply with the instructions, and the Marine fired two rounds, which resulted in the Afghan Uniformed Police member's death," the statement continued.
The incident occurred in Helmand's Sangin district, ISAF said.
Earlier Saturday, ISAF reported that three civilians and several insurgents were killed in Afghanistan.