A view of the ancient Syrian site of Palmyra showing some of the damage caused while it was held by the Islamic State, which was driven out in late March. (-/AFP/Getty Images)

At an ancient Roman amphitheater where just months ago the Islamic State staged mass beheadings, Russia on Thursday deployed a celebrated conductor and a renowned cellist on a cultural offensive to mark the liberation of Palmyra and re­inforce Russia’s role in Syria.

In place of the warplanes and special forces­ fighting here in March, President Vladimir Putin sent the Mariinsky Orchestra led by conductor Valery Gergiev and joined by cellist Sergei Roldugin, one of Putin’s close friends and a subject of recent leaks about secret offshore holdings.

The symbolism was lost on no one. Speaking by video link from Moscow, Putin told the gathering that the world should unite behind Syria to restore the historical site as a sign of hope in the battle against terrorism.

It was an odd moment of manufactured optics aimed at public vindication of Russia’s role in this five-year conflict that has killed 250,000 people and displaced millions who have sought asylum in neighboring countries of the Middle East and in Europe.

But U.S. critics and others see the intervention as an effort to prop up the autocratic Syrian leader Bashar al-Assad. And the Russian cultural entourage was another show of support for ­Assad amid mounting Western pressures to make political concessions to help end the nation’s civil war.

Vladimir Medinsky, Russia’s culture minister and the highest-ranking official to visit Palmyra on Thursday, had sharp words of condemnation for the West.

“The world community extremely neglectfully treated the threat of ISIS and international terrorism and, it seems to me, should now atone for its guilt by helping to save what can still be saved,” he said, using an acronym for the Islamic State.

“What was done here can only be compared with what the fascists did in Russia,” Medinsky said. “It is amazing that the lot of the Russian soldiers in all times in history has been to save world culture from destruction.”

The liberation of Palmyra and its 2,000-year-old ruins has become a centerpiece in Moscow’s public defense of its Syrian intervention, an ambitious venture in which Russia has sent thousands of troops and planes overseas in the country’s first military intervention outside the former Soviet Union since the disastrous Soviet invasion of Afghanistan in 1979.

In a carefully guided exhibition of its successes in the Syrian conflict, Russia flew in more than 100 international journalists, shuttling them to its Khmeimim air base in Latakia and to Palmyra, a desert city recognized as a UNESCO World Heritage site.

Palmyra was recaptured in late March by Syrian soldiers backed by Russian airstrikes — a success that Moscow says demonstrates its leadership in the fight against the Islamic State.

But Russia has also come under intense criticism from the West and its allies for offen­sives that have targeted anti-Assad rebel factions, including some backed by Washington.

A recent surge of violence by both sides in the strategic northern city of Aleppo has killed more than 250 people, including more than 50 in an airstrike last week on a hospital in a rebel-held area. The battles further eroded international efforts to impose a cease-fire between Syrian and opposition ­forces.

Assad, in a letter to Putin, vowed to prevail in Aleppo and drew comparisons to Stalingrad’s “heroic” resistance to a siege by German troops in World War II, the Associated Press reported.

In the northwestern province of Idlib, meanwhile, airstrikes killed at least 28 people Thursday in a camp for internally displaced people, according to the Syrian Observatory for Human Rights. The Britain-based monitoring group said the death toll — which includes women and children — is expected to rise.

It was unclear who carried out the attack, although Syria’s government and Russia operate warplanes over the area, which is held by rebels opposed to Assad.

The strikes follow an apparent agreement Wednesday between the United States and Russia to broker a new cease-fire for Aleppo. Activists and rebels in the city say the agreement appears to have reduced the fighting there but not completely stopped it.

A nationwide cease-fire backed by the two powers in February all but collapsed in large part because of clashes­ in Aleppo, a city divided between government and rebel control.

In Palmyra, Medinsky, the culture minister, joined Russia’s representative to UNESCO, Eleonora Mitrofanova, in viewing the damage caused by Islamic State militants across the site, spread over a desert plain about 140 miles northeast of Damascus.

Later, Russian musicians gathered amid the antiquities for a concert of Bach and other pieces featuring Gergiev and Roldugin. The cellist was among prominent Russians named last month in the Panama Papers — leaked files about secret offshore holdings. Roldugin has said he served only as a middleman for wealthy Russians buying expensive musical instruments.

Putin, in his remarks by video link, cited “hope not just for the revival of Palmyra as a cultural heritage for all humanity but for the deliverance of modern civilization from this terrible malady of international terrorism.”

Mitrofanova said a full assessment of the Palmyra damage is underway and called on world leaders to put aside political differences to help restore the site. She spoke to a group that included envoys from China and Brazil and other representatives from Africa, Asia and South America.

“If certain countries continue this two-faced game, that we love our shared cultural heritage but don’t love Assad, I think it will turn out badly” for the restoration of Palmyra, Mitrofanova said.

The push by Syrian soldiers into the Roman-era ruins of Palmyra captured a hugely significant prize for the forces­ of Assad and their Russian allies — rich in propaganda value for both sides.

But it also brought sad images of the ravages by the Islamic State against some of the world’s most famous antiquities, including statues, a 2,000-year-old lion carving and the temples of Baalshamin and Bel.

During the Islamic State’s hold on Palmyra, its fighters also used the site’s amphitheater for summary executions. Among the victims was Khaled Asaad, the retired director of Palmyra’s museum and considered among the leading scholars of the area.

After taking over Palmyra in May 2015, the Islamic State began destroying some ancient monuments, including the 1st-century Temple of Bel and the Arch of Triumph, which a Roman emperor built in about A.D. 200.

Still, Syrian archaeological officials say most of the site was either untouched or had relatively minor damage, such as gunfire pockmarks, that can be repaired by restorers.

Islamic State militants have destroyed other pre-Islamic antiquities in Syria and Iraq, including renowned artifacts and sculptures in the museum in Mosul, the group’s stronghold in northern Iraq.

Hugh Naylor in Beirut and Brian Murphy in Washington contributed to this report.