MOSCOW — The Russian Ministry of Defense on Monday released new video footage shot from a drone showing the partial destruction of the ancient Roman amphitheater in Palmyra, and warned that the Islamic State was mustering explosives to continue the destruction of the ancient city. The footage also showed the destruction of the city's tetrapylon, an arrangement of 16 columns marking the city’s main crossroads.

The city has become an important symbolic prize for Russia, which has justified its 16-month deployment in the Syrian civil war as a fight against an existential terrorist threat that it has likened to Nazism in World War II. But Russian air power has largely focused on other enemies of Syrian President Bashar al-Assad, helping him regain control over territory and key cities from other rebel groups of varying ideology.

Control over Palmyra has passed back and forth during Syria’s six-year-old civil war. Fighters from the Islamic State first captured the city in 2015. In March 2016, the city was retaken by Syrian forces backed by Russian air power and special forces.

In a dramatic publicity stunt, the Russian government flew in the Mariinsky Orchestra under the direction of Valery Gergiev and cellist Sergei Roldugin (a friend of Vladimir Putin’s) to play a three-piece concert of Bach, Prokofiev and Russian composer Rodion Shchedrin in the ancient amphitheater. The concert took place just six weeks after the city was retaken. The sound of outgoing artillery was still audible as the orchestra set up to play.

Then, with Russian and Syrian forces focused on Aleppo, the Islamic State retook control of Palmyra in mid-December. The video released by the Russian Ministry of Defense contrasts footage taken before and after the Islamic State's most recent offensive.

The Russian Ministry of Defense also said that Islamic State fighters were planning to destroy more monuments before abandoning the city, claiming it was a response to an expected offensive by the Syrian army. “This shows ISIS’s intentions to deliver explosives in order to totally destroy the remaining ancient architectural monuments before their retreat,” it said in a caption accompanying the video, using a common acronym for the Islamic State.

No visual evidence was given to support that claim.

The footage of the destruction provides a clearer image than that found in the satellite footage released last month.

As my colleagues Louisa Loveluck and Missy Ryan previously reported, Syrian state officials last month announced that they had seen satellite footage from December showing the destruction of the central part of the Roman amphitheater, the proscenium, where the Islamic State had previously held mass executions.

Irina Bokova, head of UNESCO, condemned the latest demolitions as a “war crime.”

The ancient city is one of the Middle East’s most famous Roman sites. “Once a major stop for ­cross-desert caravans, the 3rd century limestone and dolomite city was ruled by the legendary Queen Zenobia and stood as a testament to the area’s ­cosmopolitan history,” they wrote.

The footage released by the Russian military, and previously cited by the Syrian government, also showed the destruction of the tetrapylon, an arrangement of 16 columns marking the intersection of the two main boulevards in the city. Most of the columns were modern replicas, but one was original, erected in the 3rd century A.D.

The destruction of Palmyra began soon after it was seized by the Islamic State in May 2015. The extremists destroyed the Monumental Arch of Palmyra, most of the Temple of Bel and the Temple of Baalshamin.