National Park Service crews are working to remove red graffiti from the Lincoln Memorial.

It appears someone spray painted “[expletive] law” on one of the columns, the National Park Service said. It was discovered at 4:30 a.m. Tuesday.

A monument preservation crew is using a mild, gel-type paint stripper that is safe for use on historic stone. After the gel is applied on the paint, it sits for an hour and then is rinsed with clean water. The crew will evaluate after each application, but treatments will be applied as necessary until all of the graffiti is gone.

Another act of vandalism in silver spray paint was discovered on a Smithsonian wayfinding sign in the 1400 block of Constitution Avenue, NPS said.

RELATED: 1 dead, 19 inured as car hits crowd at Charlottesville rally

The vandalism comes three days after a “Unite the Right” rally turned deadly in Charlottesville, Va. Alt-right demonstrators, white nationalists, and Neo-Nazis were protesting the planned removal of a statue of Confederate Gen. Robert E. Lee.

A Confederate monument in Baltimore also was vandalized on Monday, the Baltimore Sun reported. Someone poured red paint on a 114-year-old statue of a dying Confederate soldier embraced by a winged figure of Glory.

The United States Park Police is investigating the incident; anyone with information is asked to contact them at 202-610-7515.