Russian President Vladimir Putin met Saudi Arabia’s defence minister on Sunday, Reuters reported. This is Moscow’s biggest attempt so far to reach out to enemies of Bashar al-Assad since Russia joined the conflict with air strikes.

Putin met Sheikh Mohammed bin Salman, a son of the Saudi king, on the sidelines of a Formula One race on Sunday, nearly two weeks since Moscow began bombing enemies of Assad, including rebel groups that are supported by Riyadh.

Saudi Arabia’s Foreign Minister Saud bin Faisal, appearing alongside Russia’s Sergei Lavrov, said Riyadh had concerns about Russia’s policy. Lavrov said Moscow understood Saudi concerns and the two countries shared the aim of preventing the establishment of a terrorist caliphate in Syria.