Plymouth Rock, the monument marking the landing site of the Mayflower in Massachusetts, has been covered in red spray paint, officials confirmed.
The rock is one of several monuments around the Plymouth waterfront found vandalised on Monday morning.
It is unclear if the incident is connected to the 400th anniversary this year.
It is not the first time a monument to the pilgrims has been damaged in the Massachusetts town.
The Mayflower sailed from Plymouth, UK in September 1620, with 12 “pilgrim fathers” bound for a new life. The ship landed in what became “New Plymouth”, Massachusetts on 21 December, at a spot now referred to as Plymouth Rock.
The rock is located in Pilgrim Memorial State Park by the waterfront of the US town. It is a small piece of a larger rock that was in the town at the time the pilgrims settled, according to local media.
Images posted to social media show several sites now covered in red paint including the rock, a pilgrim statue and four scallop roll statues.
Lea Filson, executive director of See Plymouth said: “Seeing this type of disrespect for the historic reminders of the Mayflower story is both sad and unsettling.
“The outpouring of concern and anger over the incident has been a positive ending to a thoughtless gesture,” she added.
Melissa Arrighi, Plymouth town manager, said on Twitter that she was saddened by the recent vandalism.
Town officials confirmed on Facebook that a clean-up operation is already under way. However it warned in a Facebook post that some memorials may need more attention.