Graffiti at the Lincoln Memorial, Tuesday. (National Park Service)

The Lincoln Memorial was vandalized with red spray paint early Tuesday, authorities said.

At about 4:30 a.m., graffiti was found on a column at the memorial, the National Park Service said in a statement. The graffiti was difficult to read, but appeared to say “[expletive] law,” the statement said.

Additional graffiti that couldn’t be read was found in silver spray paint on a Smithsonian wayfinding sign in the 1400 block of Constitution Avenue, according to the statement.

The graffiti at the Lincoln Memorial was to be removed with “a mild, gel-type architectural paint stripper that is safe for use on historic stone,” the Park Service said. The material is spread on the column and allowed to set for an hour before being removed with water. The process is repeated until the graffiti is gone.

Graffiti was found on a column at the Lincoln Memorial on Aug. 15. The graffiti was difficult to read, but appeared to say "[expletive] law." (WUSA9)

[Four memorials damaged with graffiti over holiday weekend]

“The removal has begun, but it’s a lengthy [process] that will require numerous treatments over a week or two to completely remove,” National Park Service spokesman Michael Litterst said in an email.

This is not the first time graffiti has appeared on Mall monuments this year. In February, the Washington Monument and the World War II, Lincoln and D.C. War memorials were vandalized with cryptic messages, including the phrase “Jackie shot JFK.”

The Park Service asked anyone with information about the graffiti to contact the U.S. Park Police at 202-610-7515.

Park Police spokeswoman Anna Rose said the investigation was ongoing.

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