An area in the grounds of Glastonbury Abbey is closed off from the public after vandals dug a large hole.
Staff found the damage on Thursday (11 July) within the area of the High Altar.
On Facebook a spokesperson said: "Please be aware that an act of vandalism has occurred within the area of the High Altar today.
"Someone has dug a sizeable hole within the area and it is now closed off with pedestrian barriers.
"If you see any unacceptable behaviour while visiting the abbey please report it to a member of staff immediately."
The incident has since been reported to Avon and Somerset Police.
Climbing on the ruins of the 17th century abbey is not permitted, along with removing stone or digging.
Abbey staff have warned vandals that they face prosecution for their actions and have apologised to visitors for any impact it may have on their visits.
The hole has been filled but the area remains closed to members of the public.