Environmental protesters sprayed paint on Britain's Stonehenge on Wednesday, with footage online showing orange marks covering some of the stones of the world-famous prehistoric megalithic structure.
Two people have been arrested on suspicion of damaging the ancient monument, local police said in a statement.
In video released by environmental group Just Stop Oil, two protesters were seen running towards two of Stonehenge's megaliths and spraying paint as another person attempted to stop them.
The monument in southern England is a UNESCO World Heritage Site and one of Britain's most visited tourist spots.
Just Stop Oil has gained prominence in Britain for disruptive environmental protests, with its activists shutting down major roads, disrupting cultural and sporting events and even throwing soup at a Van Gogh painting.
The group wants the British government to end the extraction and burning of oil, gas and coal by 2030.
English Heritage, the charity that cares for Stonehenge, did not immediately respond to a request for comment.