Russia is sending more warships to Syria for operations against extremist groups.

The naval destroyer Smetlivy has departed from the Crimean port of Sevastopol. The heavily-armed ship is heading for the Greek port of Piraeus before it joins its battle group in Syria.

The vessel took part in previous operations in Syria in 2013 and 2015. Meanwhile, a Russian naval fleet is also on its way to the Mediterranean. The fleet includes Russia's only aircraft-carrier Kuznetsov, a cruiser and several destroyers.