Ancient statues and other artefacts have been stolen from Syria's National Museum in the capital, officials say.
The theft was noticed on the start of the week, when employees apparently found that a doorway had been damaged from the inside.
The multiple missing pieces were made of marble and originated to the Roman era, one official stated to the Associated Press.
The nation's antiquities authority said it had launched a probe to identify the "details surrounding the loss of a group of exhibits", and that actions had been implemented to strengthen security and monitoring systems.
The chief of domestic security in the capital area, Security Chief Atkeh, was referenced by the state-run Sana news agency as saying that law enforcement were investigating the theft, which he said had targeted several "historical artifacts and unique items".
He continued that security personnel at the facility and other individuals were being questioned.
The Damascus Museum, which was established in 1919, contains the most important historical artifacts in the country.
It features clay cuneiform tablets tracing back to the 14th Century BC from an ancient city, where indications of the oldest known linguistic system was found; Greco-Roman period ancient art from historical site, among the foremost cultural centres of the ancient world; and a 3rd Century AD Jewish temple that was established at Dura Europos.
The institution was forced to close in the early 2010s, one year after the beginning of the destructive conflict. Most of the artifacts was evacuated and preserved at undisclosed sites to safeguard them.
It reopened partially in recent years and returned to normal in the beginning of the year, one month after rebel forces deposed President Bashar al-Assad.
Every one of the country's cultural landmarks were harmed or partially destroyed during the internal struggle.
The militant faction demolished numerous religious structures and historical sites at the archaeological site, asserting that they were against their beliefs. Unesco condemned the demolition as a atrocity.
Many artefacts were also destroyed or looted from archaeological sites and museums.