Red paint was splashed across the sign outside President Donald Trump's golf club near his Florida estate.
Images posted online by The Palm Beach Post show a worker cleaning red paint Sunday morning from the stone sign at the entrance to the Trump International Golf Club in West Palm Beach.
Palm Beach Sheriff's Office spokeswoman Therese Barbera said the U.S. Secret Service was investigating.
Secret Service spokesman Joseph Casey referred questions to the sheriff's office.
Images posted online by ABC News early Sunday showed large splotches of red paint obscuring some of the letters on the polished stone surface.
The golf club is less than 8 kilometers (5 miles) from Trump's Mar-a-Lago estate. Trump attended Easter services at a nearby Episcopal church.