ISIS militants have reputedly wrecked two additional sites in Palmyra, in acts of cultural oppression that began just weeks after the terror group regained control of the ancient city from Syrian government forces. The damage to the tetrapylon — a cubic structure composed of four gateways — and to the city’s Roman amphitheater were confirmed by Syria’s Directorate-General of Antiquities & Museums (DGAM), which shared satellite imagery captured by space imagery provider DigitalGlobe.

DGAM’s announcement emerged last week at a moment when much of the world’s attention was focused on Washington, DC, but the destruction, the agency said, likely occurred between December 26 and January 10. According to the Boston-based American Schools of Oriental Research Cultural Heritage Initiatives (ASOR CHI), which also shared the aerial photos, the imagery “shows significant damage to the tetrapylon and the Roman amphitheater, likely the result of intentional destructions by ISIL [aka ISIS], although we are currently unable to verify the exact cause.”

The nonprofit believes the militant group used explosives to strike the tetrapylon, leaving just two of its columns standing. Consisting of four large plinths that each support four columns, the structure had underwent reconstruction by DGAM in 1963, and only one of the original pink Egyptian granite columns had survived over time. It is unclear whether that pillar is among the two that remain among the wreckage, or whether solely modern replicas mark the site of the ancient gateway.

The nearby, late 2nd-century Roman amphitheater, according to ASOR CHI, appears to have “sustained damage” to its scaenae frons. Never finished, the stage just last May hosted a performance by the Symphony Orchestra of St. Petersburg intended as a peace concert, followed by a concert to celebrate Palmyra’s recapture by the Syrian government. The festivities seemed surreal then, especially considering the amphitheater allegedly was used for public executions by ISIS in 2015. But the ancient arena has allegedly become the gruesome stage once more for beheadings: the UK-based monitoring group Syrian Observatory for Human Rights has reported that ISIS executed 12 people on January 19, including teachers, government workers, and soldiers. The murders, it said, also occurred in the courtyard of the Palmyra Museum — where terrorists also apparently killed Khaled al-Asaad, the city’s former Chief of Antiquities.

UNESCO’s Director-General Irina Bokova condemned the destruction as “a new war crime” and urged in a statement that “the protection of heritage is inseparable from the protection of human lives, and we must all unite to put this at the center of all efforts to build peace”

“The tetrapylon was an architectural symbol of the spirit of the encounter and openness of Palmyra — and this is also one of the reasons why it has been destroyed,” Bokova said. “Its position and shape are unique in ancient architecture and testified to the specificity of Palmyrene identity, as a source of pride and dignity for all Syrians today.”

News of the last week’s executions coincided with the Russian government’s announcement that it has startling intelligence that suggests even more cultural destruction to come.

“We have received information, confirmed by several sources, that a large amount of explosives has been brought into the Palmyra area and that the terrorists plan on destroying the city’s world-class historical legacy,” as senior Russian defense ministry official Lieutenant-General Sergei Rudskoi said last week. The tetrapylon and amphitheater join an already too-long list of structures that ISIS has attacked at the the UNESCO Heritage Site. Since 2014, places attacked by explosives and even bulldozers includes mausoleums, the nearly 2,000-year-old Temple of Baalshamin, the Temple of Bel, and the city’s famous Arch of Triumph.