Valuable statues and additional items have been stolen from the National Museum of Syria in Damascus, authorities report.
The robbery was found on the start of the week, when staff apparently found that a doorway had been broken from the inside.
The six missing sculptures were crafted from marble and originated to the Roman period, a source informed the Associated Press.
Syria's Directorate-General for Antiquities and Museums said it had initiated an inquiry to establish the "circumstances surrounding the theft of a collection of exhibits", and that measures had been taken to strengthen protection and surveillance.
The chief of internal security in Damascus province, Security Chief Atkeh, was referenced by the state-run Sana news agency as declaring that law enforcement were probing the robbery, which he said had affected several "historical artifacts and valuable objects".
He continued that security personnel at the facility and other individuals were being interrogated.
The National Museum, which was founded in 1919, holds the most important historical artifacts in the country.
It contains historical records tracing back to the 14th Century BC from historical site, where indications of the earliest complete alphabet was found; early centuries CE ancient art from historical site, among the foremost historical locations of the historical period; and a 3rd Century AD synagogue that was constructed at Dura Europos.
The institution was had to cease operations in the early 2010s, one year after the outbreak of the internal strife. The majority of the artifacts was removed and stored at secure places to protect them.
It partially resumed in 2018 and returned to normal in the beginning of the year, four weeks after insurgents overthrew the Assad regime.
All six of the country's cultural landmarks were harmed or partly ruined during the civil war.
The IS organization blew up multiple temples and other structures at the archaeological site, claiming that they were un-Islamic. The cultural organization denounced the damage as a war crime.
Many cultural items were also damaged or looted from archaeological sites and museums.