The ancient Baal Shamin temple of Palmyra, at Tadmur, Syria. About one-third of the ancient city of Palmyra, Syria, home of historic Roman ruins, was under Islamic State control on Wednesday, May 20, 2015. File Photo by wikimedia.org/ B. Gagnon.

TADMUR , Syria, May 20 (UPI) -- About one-third of the ancient city of Palmyra, Syria, home of historic Roman ruins, was under Islamic State control Wednesday.

The city, also known as Tadmur, is the site of 120 acres of ruined buildings from the 1st century A.D., when it was an outpost of the Roman Empire.


The collection of monuments and buildings was put on UNESCO's World Heritage danger list in 2013. The violence has provoked global worries that IS, which has been known to destroy iconic examples of antiquities it considers idolatrous, may put the monuments at risk.

It is regarded as one of the Middle East's most exceptional archeological sites.

IS overran the northern part of the city after battles with government troops and militias, and the British-based activist group Syrian Observatory for Human Rights said one-third of Tadmur was occupied. It added militias have begun evacuating residents.

"I am deeply concerned by the situation at the site of Palmyra. The fighting is putting at risk one of the most significant sites in the Middle East, and its civilian population. I reiterate my appeal for an immediate cessation of hostilities at the site. I further call on the international community to do everything in its power to protect the affected civilian population and safeguard the unique cultural heritage of Palmyra," said UNESCO Director-General Irina Bokova in a statement.