By Nathan Howard

WASHINGTON, June 11 (Reuters) - U.S. authorities were responding on Thursday to what appeared to be a large tracing of "8647" into the grounds of the National Mall in Washington, D.C.

A Reuters photographer atop the Washington Monument saw the apparent tracing in the grass near the World War Two Memorial shortly before officials arrived. It shows the numbers eight, six and seven, but a four is not clearly defined.

U.S. Park Police and members of the National Guard were responding to the scene.

It references the slang term "86," originating in the restaurant industry meaning to expel or "get rid" of something, and Trump as the 47th U.S. president.

It was unclear how the markings in the grass were made. In those areas the grass is brown, in contrast to the surrounding green grass.

(Reporting by Nathan Howard; Writing by Andrew Goudsward; Editing by Michael Learmonth and Daniel Wallis)