Syria's ancient town of Palmyra was seized by Islamic State militants last week. Reports on Sunday put the death toll at about 400 civilians after ISIS took control, ransacked a museum and barricaded the town.

ISIS has made a public show of destroying what they see as "false idols" in museums and cultural sites. However, Antiquities director Maamoun Abdulkarim said much of Palmyra museum's collections were already taken to Damascus for safekeeping. The militants likely destroyed modern plaster copies of ancient relics. 

Abdulkarim added, "But there are still the large items, like the sarcophagi, which weigh three or four tonnes and we could not move, those are what worry me."

On the outskirts of Palmyra, an UNESCO World Heritage Site has also been captured. Destruction the 2,000-year-old Roman-era city would be "an enormous loss to humanity," say Unesco officials.

ISIS has already destroyed much of Nimrud, among Iraq's most significant archaelogical sites, and the Mosul Library, which contained 8,000 ancient manuscripts, among other cultural places and antiquities.

The loss of Syria's cultural heritage represents the loss of far more than some tourist attractions - it is the loss of connection between multiple generations," said Dr. David Roberts, King's College, London.