WASHINGTON (AP) — A power outage along the National Mall has left several museums and other buildings in the dark.

Power went out in the early Friday afternoon and Pepco spokesman Marcus Beal said they’re investigating the cause of the outage and how long repairs will take.

Smithsonian spokeswoman Linda St. Thomas says the outage has closed some of the institution’s museums, including the Hirshhorn Museum, Sackler Gallery and the National Museum of the American Indian.

St. Thomas says whether they reopen Friday depends on how quickly power is restored.

The Air and Space Museum, the Smithsonian Institution Building, known as the Castle and the Smithsonian’s other museums in Washington are not affected.

The Newseum and U.S. Holocaust Museum are also affected by the outage.