Federal authorities are investigating what appears to be large numerical markings etched into the grass of the National Mall in Washington, D.C.

The markings, which appear to spell either "8647" or "86 47," were visible from elevated positions including the Washington Monument as of Thursday afternoon. Live webcam footage from atop the monument showed the etchings across the lawn area.

According to multiple reports, the number "8" appears most prominently in the grass, while the remaining digits "6," "4," and "7" are less visible but still discernible. A Reuters photographer also observed the markings from the Washington Monument.

The National Mall, which stretches from the U.S. Capitol to the Lincoln Memorial, is managed by the National Park Service and serves as the site for major national events and demonstrations. The area is heavily monitored due to its significance as a national landmark.

Authorities have not yet released details about how the markings were created, when they may have appeared, or any potential connection to recent events. The investigation remains ongoing.