The National Park Service says the Washington Monument is temporarily closed again after another power failure.

The agency announced Monday that the monument was closed Monday morning after the elevator lost power around 9:30 p.m. Sunday.

Officials say no one was on board when it lost power, and rangers escorted one visitor from the observation level to the ground by the stairs.

Electricians and elevators technicians are working to find the source of the electrical problem. The monument was closed on Thursday and Friday morning last week after an electrical problem caused a power failure on Wednesday evening.