Lights at the Washington Monument were back on Wednesday after going dark overnight in the latest sign of trouble for the shuttered obelisk, one of the most popular tourist draws in the U.S. capital.


Lights on the 555-foot monument, about a half-mile south of the White House, went out around 7 p.m. on Tuesday. But they were on when electricians arrived on Wednesday morning, National Park Service spokesman Mike Litterst said in an email.


He said the lighting system's clock was likely out of synchronization, though red aircraft warning lights were unaffected.


"Staff are working to correct the problem and the lights are expected to be on this evening as normal," Litterst said.


The lighting trouble comes about four months after the Washington landmark, which was damaged in a 2011 earthquake, was shut down because of chronic problems with its elevator.


The National Park Service said last month the monument, which draws about 600,000 visitors a year, would reopen in 2019.

(Reporting by Ian Simpson; Editing by Dan Grebler)