Islamic State posted photographs online which it said were taken in the central Syrian city of Palmyra and appeared to show its ancient ruins unharmed since the hardline group seized it from government forces.
Reuters was not able to independently confirm the authenticity of the photographs posted on jihadi forums by the Islamic State's media branch. Activists in contact with people inside the city have also said there has been no damage to the UNSECO World Heritage site since the takeover.
Islamic State is an offshoot of Al-Qaeda that has seized territory in Syria and Iraq and is the target of a US-led air strike campaign in both countries.
The group has destroyed antiquities in neighboring Iraq and Syria's antiquities chief has voiced fears it might now devastate Palmyra, home to renowned Roman ruins including temples, colonnades and an amphitheater.
On Wednesday the group shot dead around 20 men in the amphitheater, accusing them of being government supporters, the Syrian Observatory for Human Rights monitoring group said.
It has said the group has killed at least 200 people and taken around 600 captive in and around the city, which is also known as Tadmur.
The 10 images were published as a photographic report entitled "The ancient city of Tadmur" and showed the inside and entrance to the amphitheater.
It appeared to have an Islamic State flag flying on top of it. There were also pictures of columns and arches.
A separate photo report claimed to show the city's prison in control of the group. It included images of an entrance, cell doors, an empty single cell and collective detention room. A picture of an empty office inside the jail had an image of late Syrian President Hafez al-Assad on the wall.
The Syrian air force has carried out airstrikes in and around Palmyra. US-led forces, whose campaign US officials say is not coordinated with Damascus, have not bombed the city, which sits on a crossroads leading westwards to Homs city and the capital.