A video released by the self-proclaimed Islamic State on social media shows members of the group destroying archeological artifacts at the Mosul Museum in Iraq.
The group has been raiding museums and libraries and destroying historical masterpieces, despite earlier warnings that the region's cultural heritage was under threat after the militants proclaimed a "caliphate" there last June.
The video shows men smashing statues with sledgehammers and even drilling through some artifacts, including a rare winged Assyrian bull, representing an ancient deity, that dates back to the 7th century B.C.
"Muslims, these artifacts that are behind me were idols and gods worshipped by people who lived centuries ago instead of Allah," a man says to the camera at the beginning of the video. "Our prophet ordered us to remove all these statues as his followers did when they conquered nations."
It's not clear when the video was filmed, but it's not the first time Islamic State militants have attacked cultural artifacts in Mosul — the largest city controlled by the Sunni Muslim group.
In January, militants broke into the Central Library of Mosul and stole more than 2,000 books including children's books, poetry, and philosophy and scientific texts, including some dating back to the Ottoman Empire.
The Islamic State members reportedly told local residents that, "these books promote infidelity and call for disobeying Allah. So they will be burned."
The University of Mosul's library was similarly raided, and in recent days, photos emerged of the militants reportedly burning as many as 8,000 rare books and manuscripts.
The group has also been destroying architectural landmarks throughout the region, including churches, shrines and Muslim holy sites it views as heretical, and financing its operations through the looting and sale of ancient artifacts.
The area of land in Iraq currently under militant control holds nearly 1,800 of the country's 12,000 registered archaeological sites. A spokesman from the UN's cultural heritage agency, UNESCO, said Thursday that, "The destruction of cultural heritage is reprehensible and criminal," and that the organization was looking into the video.
"I'm totally shocked," Amir al-Jumaili, a professor at the Archaeology College in Mosul, told the AP. "It's a catastrophe. With the destruction of these artifacts, we can no longer be proud of Mosul's civilization."