Maryland officer shot as active shooter situation unfolds at police station
Active shooter exercise (Wikimedia Commons)

A police officer was shot and critically wounded on Sunday as an active-shooter situation unfolded outside a Prince George's County police station in the Maryland suburbs of Washington, authorities said on Twitter.

There were no immediate details on the circumstances of the shooting as police urged residents in a tweet to stay inside and away from the police station in the vicinity of Landover, Maryland, about 8 miles east of the nation's capital.

Police also said a shooter or shooters remained at large.

A dispatch clerk answering the phone at the station declined to provide any information.

(Reporting by Brendan O'Brien and Frank McGurty; Editing by Peter Cooney and Jonathan Oatis)