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DAMASCUS, Syria — ISIS militants on Sunday blew up the temple of Baal Shamin, one of the most important sites in Syria's ancient city of Palmyra, said Maamoun Abdul Karim, the country's antiquities chief.

The temple bombing would be the first time that the insurgents, who control large parts of Syria and Iraq and who captured Palmyra in May, have damaged monumental Roman-era ruins.

The ancient city of Palmyra in central Syria. Youssef Badawi / EPA

"We have said repeatedly the next phase would be one of terrorizing people and when they have time they will begin destroying temples," Abdul Karim told Reuters.

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"I am seeing Palmyra being destroyed in front of my eyes," he added. "God help us in the days to come."

A week ago, the militants beheaded Khaled Asaad, an 82-year-old scholar who worked for more than 50 years as head of antiquities in Palmyra, after detaining and interrogating him for more than a month.

Related: ISIS Beheads Archaeology 'Pioneer' Khaled al-Asaad in Palmyra

Before ISIS captured the city, Syrian officials said they moved hundreds of ancient statues to safe locations out of concern that the militants would destroy them. In June, ISIS blew up two ancient shrines in Palmyra that weren't part of its Roman-era structures but that the militants regarded as pagan and sacrilegious.

The militants were also beginning excavation for gold and giving licenses for illicit excavation of the city's treasures, Abdul Karim added.

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