Authorities say an off-duty sheriff's deputy was involved in a shooting when two men tried to rob him.

Prince George's County police tell local media two men approached the off-duty deputy who was not in uniform while walking in the D.C. suburb of Largo early Sunday. One of the men, who police say was wearing a mask and armed with a handgun, said it was a robbery and fired at the deputy.

The deputy, who was armed with his duty weapon, fired back.

The two men fled in a vehicle driven by a third person.

The Prince George's County police department is investigating the assault against the deputy.

The deputy, who hasn't been identified, has been placed on administrative leave. The Prince George's County Sheriff's Office Internal Affairs Division will conduct an administrative investigation.