Islamic State (ISIS) jihadists have destroyed a temple at Syria’s ancient ruins of Palmyra, activists said Sunday, according to The Associated Press (AP).

The move realizes the worst fears archaeologists had for the 2,000-year-old Roman-era city, after the extremists seized it and beheaded a local scholar.

Palmyra, one of the Middle East’s most spectacular archaeological sites and a UNESCO World Heritage site, sits near the modern Syrian city of the same name. Activists said ISIS used explosives to blow up the Baalshamin Temple on its grounds, the blast so powerful it also damaged some of the Roman columns around it.

The Britain-based Syrian Observatory for Human Rights said Sunday night that the temple was blown up a month ago. Turkey-based activist Osama al-Khatib, who is originally from Palmyra, said the temple was blown up Sunday.

Both said the extremists used a large amount of explosives to destroy it, according to AP. They relied on information from those still in Palmyra and the discrepancy in their accounts could not be immediately reconciled, though such contradictory information is common in Syria’s long civil war.

The fate of the nearby Temple of Bel, dedicated to the Semitic god Bel, was not immediately known. ISIS supporters on social media also did not immediately mention the temple’s destruction, according to AP.

In June, Islamic State blew up two ancient shrines in Palmyra that were not part of its Roman-era structures but which they regarded as pagan and sacrilegious.

The group’s destruction of artifacts was condemned by the UN’s cultural body, UNESCO, which described it as an attempt to strip the people of their heritage in order “to enslave them”.

The Sunni extremists, who have imposed a violent interpretation of Islamic law across their self-declared “caliphate” in territory they control in Syria and Iraq, claim ancient relics promote idolatry and say they are destroying them as part of their purge of paganism.

However, they are also believed to sell off looted antiquities, bringing in significant sums of cash.

Al-Khatib said the Baalshamin Temple is about 500 meters (550 yards) from the Palmyra’s famous amphitheatre where the group killed more than 20 Syrian soldiers after they captured the historic town in May.

In another atrocity in Palmyra, ISIS jihadists last week beheaded an antiquities scholar in the city and hung his body on a column in a main square.

The scholar, 82-year-old Khaled Asaad, had worked for over 50 years as head of antiquities in Palmyra.