Police surround empty shed

US police held a three hour armed standoff outside a shed in Salt Lake City only to discover there was nobody inside.

The call-out began after a woman living in a house next to the shed told police she had seen her roommate's estranged boyfriend enter the shed with a gun, reported the Associated Press.

Officers secured the area, and after searching the house and calling in police dogs, discovered the shed was locked and there was no-one inside.

Neighbours were evacuated and police shut down portions of nearby streets before the empty shed was revealed.