Six people were arrested in England after a group burned a section of grass at Stonehenge and climbed on top of the ancient monument.
The four men and two women were arrested on suspicion of offences under the Stonehenge Regulations Act 1997 in the early hours of Tuesday morning.
In total, 14 people carrying flaming torches are believed to have entered the stone circle at the ancient Wiltshire site at about midnight.
They burned sections of the grass within the circle and spilled paraffin within it, with two members of the group then climbing on top of the stones.
Wiltshire Police arrested six people in connection with damage to the monument, including a 50-year-old man from Taunton also suspected of possessing cannabis.
The other five arrested were a 44-year-old man with no fixed abode, a 61-year-old man from Windsor, a 52-year-old woman from Yeovil, a 48-year-old man from Worthing and a 45-year-old woman from Windsor.
A force spokeswoman said: "All six were taken to custody at Melksham Police Station. Three have been given adult cautions in relation to the incident and three were released with no further police action to be taken."
Staff at Stonehenge said they repeatedly requested the group to leave the monument, with one physically threatened by a man blowing flames towards him.
It is understood the incident was a protest by a group opposed to changes recently announced for the Summer Solstice at Stonehenge.
Changes include the introduction of a car parking charge and a ban on alcohol within the monument field.
Kate Davies, Stonehenge General Manager, said: "Last night, the grass in the centre of the stone circle was scorched and doused with paraffin and people climbed on top of the ancient stones.
"How can people who claim to honour the stones deliberately disrespect and damage them like this? As guardians of Stonehenge, we cannot stand by and allow people to vandalise the monument in response to changes intended to protect and conserve it.
"We've had a lot of support for the changes to Summer Solstice not only from the public but from within the pagan and druid community.
"These new changes are necessary if we are to keep what makes celebrating the Summer Solstice at Stonehenge so special."
English Heritage experts are currently assessing the extent of the damage.
According to the Stonehenge Regulations Act of 1997, it is an offence to climb on the monument, interfere with plants or grass within it, bring any animal to the site, light a fire or firework there or enter or be on any part of the site without reasonable excuse.