The man splashed red paint and wrote a profane message on the base of the Washington, DC monument, police said.
Park Police are unsure at this time if the temporary closure will affect public visitation of the monument which would normally reopen at 10:00 am the following day.
After years of construction and repairs, the Washington Monument reopens to the public.
Repairs and cleaning of the paint will be handled by National Park Service conservators.
The iconic structure on the National Mall is named for George Washington, the country’s first president.
The obelisk was completed in 1888.