MOSCOW -- An orchestra from one of Russia’s most famous theaters today played a concert in a Roman amphitheater in the ancient city of Palmyra to triumph its recapture by Syrian government forces.

Syrian troops retook Palmyra from ISIS militants in late-March under the cover of Russian airstrikes and artillery.

Today, St. Petersburg’s Mariinsky Theater Orchestra performed on Palmyra’s 2,000-year-old Roman stage in a surreal scene among the desert ruins, which ISIS had used as an execution site. The orchestra played Bach and a symphony by Sergei Prokofiev to a crowd of Russian and Syrian soldiers and civilians, beneath a facade where the Roman Emperor Nero had once ordered a statue of himself placed.

The face of Russia’s President Vladimir Putin appeared on a screen inside the amphitheater by video-link to address them. “Thank you for this surprising humanitarian action,” Putin told the crowd.

The concert, titled “A Prayer for Palmyra,” was broadcast live by Russian state television. The concert’s conductor, Valery Gergiev, told the audience the concert was protesting “against barbarians who have destroyed monuments of world culture.”

Palmyra is a UNESCO World Heritage site, the sprawling well-preserved remains of an ancient city that was once Syria’s most popular tourist attraction. ISIS forces seized the city last May and began dynamiting some of its architectural sites that the terror group believes were idolatrous, causing extensive damage.

After Palmyra was retaken, the Russian military de-mined the ruins, removing thousands of ISIS booby traps, according to the country’s defense ministry.

Moscow and the Syrian government have trumpeted Palmyra’s recapture as a symbol of how their campaign is rescuing civilization in Syria after five years of savage warfare. Today’s concert seemed intended to underscore that idea.

Putin said the concert was meant as as sign of hope “for the deliverance of modern civilization from this terrible plague, from international terrorism.”

But even as the Russian orchestra played, fighting continued across Syria, with reports that an airstrike had struck a refugee camp, killing dozens. Meanwhile, Syrian President Bashar al-Assad pledged that his forces would eventually achieve victory over rebels in Aleppo, despite a 48-hour truce brokered by the United States there Wednesday. The comments suggested Assad had little intention of engaging seriously in peace negotiations with rebels that had all but collapsed last month.

Monitoring groups estimate over 400,000 people have been killed in Syria since 2011, the great majority by forces loyal to Assad, many through indiscriminate barrel bombing and airstrikes. Leaked documents acquired by international rights groups have shown tens of thousands have been brutally tortured by Assad’s security services, beaten, suffocated, electrocuted, some with limbs drilled, their eyes gouged out.

Russia has been supporting Assad’s government with a ferocious air campaign targeting rebels, as well as with advisers on the ground. Russian aircraft in Syria have been accused by rights groups of indiscriminately bombing hospitals in rebel areas and causing hundreds of civilian casualties. Rebel groups last week blamed Russia for airstrikes on a hospital in Aleppo that killed at least 27 people.

Although Aleppo was quieter today, rebels reported shelling in villages near the city, according to The Associated Press. ISIS fighters, meanwhile, seized gas fields in the desert near Palmyra, the first advances by the group there since the city was retaken, Reuters reported.

Staging musical concerts on the sites of its military successes is becoming a signature move for the Kremlin. Valery Gergiev, the conductor at Palmyra known for his outspoken support of Putin, also led the orchestra when it played in the breakaway republic of South Ossetia after Russian troops routed Georgian troops in a 2008 war there.

Popular Russian singers have also held concerts in Crimea and eastern Ukraine after pro-Russian rule was established there.