This story was updated at 5:45 p.m. ET with UNITAR-UNOSAT satellite imagery.
Islamic State militants have destroyed one of the most historically significant temples in the ancient Syrian city of Palmyra, in the group's latest atrocity at the 2,000-year-old site.
While the extent of the damage was initially unclear, with activists -- including a Palmyra resident -- telling the Associated Press that the militants bombed the ancient Temple of Bel on Sunday, satellite images soon surfaced confirming the worst.
"We can confirm destruction of the main building of the Temple of Bel as well as a row of columns in its immediate vicinity," said Einar Bjorgo, Manager at UNOSAT, in a statement sent to Mashable.
Amr al-Azm, a former Syrian government antiquities official who now is a professor at Shawnee State University in Ohio, said he believed many explosives were used and the damage to the Temple of Bel was likely extensive. He cautioned that information remains scarce.
"This is the most devastating act yet in my opinion. It truly demonstrates ISIS' ability to act with impunity and the impotence of the international community to stop them," al-Azm said.
Earlier this month, Islamic State militants executed a prominent Syrian antiquities scholar who had worked in Palmyra for decades. Khaled al-Asaad, 82, was a leading researcher at the 2,000-year-old site.
Islamic State militants reportedly interrogated Asaad about the location of archeological treasures in Palmyra before killing him and displaying his body on a public street. UNESCO condemned the militants, equating their actions to war crimes.
Palmyra: the brutal systematic destruction of world heritage is a war crime & the perpetrators must be accountable for their actions— Irina Bokova (@IrinaBokova) August 24, 2015
Palmyra was one of the important markets and caravan cities of the Roman Empire, linking it to India, China and Persia -- something reflected in the city's arts and architecture.
The ruins are "one of the most important cultural centers of the ancient world," according to UNESCO. The site blends Greek and Roman techniques with Persian influences.
Islamic State militants have been destroying ancient sites and antiquities while continuing to take control of territory across Iraq and Syria in recent months. Their extremist version of Islam views religious imagery -- and structures contained in many ancient sites -- as idolatry.