Increasingly frustrated by the Islamic State’s brazen pillaging and trafficking of artifacts in the Middle East, all members of the United Nations agreed on Thursday to take new steps intended to thwart and prosecute antiquities smugglers, ensure the return of plundered ancient treasures and counter what diplomats described as “cultural cleansing,” a new tactic of war to spread hatred and erase the heritage of civilizations.

The resolution adopted unanimously by the 193-nation General Assembly was focused on the threat to Iraq. But it amounted to the broadest international condemnation of the cultural destruction and vandalism wrought by the fighters of the Islamic State, also known as ISIS, ISIL and Daesh, who have videotaped themselves using bulldozers, explosives and sledgehammers on some of the most prized archaeological sites in the world.

So far all the sites have been in or near the northern Iraqi city of Mosul, which ISIS seized last year, but the group’s invasion of the storied Syrian city of Palmyra, known for its ancient ruins, a week ago raised new alarms.

Iraqi officials, who were major sponsors of the resolution, have said ISIS militants seek to sell what they cannot destroy, and the country’s United Nations ambassador, Mohamed Ali Alhakim, has said the extremist group earns as much as $100 million annually from antiquities trading. Although the origin of that figure is unclear, international police officials have said the looting of antiquities in war-ravaged and unstable countries is a lucrative business.