Surveillance cameras are situated on both sides of the monument, but it remains unclear if footage of the perp or perps was captured.
"I have no idea who would want to do something like that," a passer-by told NBC Washington. "To me, it's defacing America. It's not just defacing the Lincoln Memorial, but it's something against all of America."
Cleaning crews were called in this morning, but it's unknown how long it will be before the Memorial is once again open to the public.
[photos via AP]