Islamic State (ISIS) terrorists have destroyed part of the Roman Theater and the legendary four-column structure ‘Tetrapylon’ in the ancient city of Palmyra, Syrian antiquities chief Maamoun Abdulkarim told Reuters Friday.

The facade of the Roman Theater has been completely destroyed, Syrian state TV reported, while the scale of damage is currently unknown.

ISIS took control of Palmyra from Syrian troops in December for the second time, after the city was liberated by Syria’s government forces and their militia allies, backed by Russian air forces, after first losing it in 2015.