Federal authorities launched an investigation after a large '8647' marking appeared on the National Mall near the World War II Memorial in Washington, DC.
The unusual display was first observed by a Reuters photographer from atop the Washington Monument.
The US Department of the Interior described the incident as 'deranged vandalism' and said the US Park Police would investigate and pursue those responsible.
Authorities have not yet determined how the marking was created, but officials have collected grass samples and laboratory testing is underway.
The term '8647' has become a political slogan used by some critics of Trump, combining '86,' a slang expression meaning to remove or reject, with '47,' a reference to Trump as the 47th president of the United States.
