Officials say an Afghan police officer opened fire inside a police station while U.S. forces were visiting, sparking a firefight that killed two U.S. troops and three Afghan policemen.

Monday's incident in Wardak province appears to be the latest in a series of insider attacks against coalition and Afghan forces. It comes a day after a deadline given by Afghans for U.S. special forces to withdraw from the province.

Deputy provincial Police Chief Abdul Razaq Koraishi says three Afghan officers were killed. A coalition military official says two U.S. forces were killed. The official spoke on condition of anonymity to disclose information pending an official statement.

The majority of U.S. troops in Wardak are special operations forces.