ISIS militants have demolished parts of the ancient monastery of Saint Eliane in Qaryatain, a strategic town located in the central Syrian province of Homs which has been captured earlier this month.
ISIS-linked Twitter accounts posted pictures of the destruction of the monastery, which dates to the first Christian centuries, showing bulldozers destroying the Saint Eliane monastery.
A Christian clergyman, who spoke on Friday on the condition of anonymity, said ISIS militants also wrecked an Assyrian Catholic church inside the monastery.
ISIS earlier vowed to destroy the statues and shrines as the group considers them examples of idolatry.
Since capturing parts of Syria and Iraq, ISIS militants have destroyed several mosques, churches and archaeological sites.
Earlier in March, ISIS exploded part of the ancient monastery of Mar Behnam in Iraq, near the town of Qaraqosh, south-east of Mosul.
Photos on social media show that the 4th-century monastery's tomb complex of Mar (Saint) Behnam and Mart (Saint) Sarah was reduced to debris.
ISIS militants also destroyed the ruins of the Assyrian city of Nimrud and artifacts in the Mosul Museum earlier this year, a move that sparked outrage from the international community.
This week, ISIS militants beheaded the renowned antiquities scholar Khaled al Asaad in the ancient Syrian city of Palmyra.
Activists and his relatives said that the militants hung his mutilated body on a column in a main square of the historic site because he apparently refused to reveal where valuable artifacts had been moved for safekeeping.