Watch Russian orchestra perform concert in Palmyra after troops reclaimed city from Isis

Russia's Mariinsky Theatre staged a surprise concert in the amphitheatre of the Syrian city of Palmyra on 5 May, just weeks after regime forces seized back the ancient city from Islamic State (Isis).

The concert, held in the ruins where IS (Isis/Daesh) used to carry out executions, saw Valery Gergiev, a close associate of President Vladimir Putin, conduct the Mariinsky orchestra.

Sergei Roldugin, a cellist friend of Putin's, also performed. Media reports based on the leaked Panama Papers from law firm Mossack Fonseca alleged that Roldugin had quietly built up a sprawling business empire involved in offshore transactions that might be linked to the Russian leader. He has denied any wrongdoing.

Putin, addressing the audience by video link from his Russian Black Sea residence of Sochi, called terrorism a contagion the world needed to rid itself of and said the fact the concert was taking place at all was "surprising".

"(There is) hope not only for the revival of Palmyra as a heritage of all mankind, but also the deliverance of modern civilisation from this terrible contagion, from international terrorism. And for this it is necessary that any success in fighting against it must be perceived by all, without exception, as a collective victory, and every victim of terror must be seen everywhere and always as a personal loss and personal pain. Only such an attitude to this absolute evil will help us to ultimately beat it," said Putin.

Gergiev, a long-time Putin supporter, described the concert as a protest against the barbarism and violence exhibited by IS militants who had destroyed parts of the Unesco World Heritage Site in Palmyra.

The event was made public just hours before it began. Russian and Syrian military personnel as well as locals could be seen in the audience. Russian special forces called in air strikes in March to help the Syrian government retake the city and Russian engineers later demined the historic part of Palmyra.

Thursday's concert had echoes of a performance conducted by Gergiev in August 2008, when the Mariinsky performed in front of the bombed-out parliament of the self-proclaimed Republic of South Ossetia after Russian forces defeated the Georgian army in a short war over the territory.

Additional reporting by Reuters