Russian missiles 'destroy' Islamic State base in Syria
"A missile strike with three Kalibr missiles destroyed a command post with large numbers of militants and armed vehicles and also a large weapons and ammunition depot," the Russian defence ministry said in a statement posted on Facebook on Tuesday.
It said the strikes targeted the area around the town of Abu Kamal, one of the few remaining urban strongholds of IS in Syria.
The ministry added it could confirm "the destruction of all the given targets".
It posted a video on Twitter of a missile blasting out of the sea.
There have been heavy clashes between the Syrian army and the Islamic state group in the city of Deir az-Zour, capital of the province of the same name in eastern Syria.
Russia said on Tuesday that its Veliky Novgorod submarine carried out four cruise missile strikes on terrorist groups since it was deployed to the Mediterranean in late August.
The submarines are covered from Syria by Moscow's S-300 and S-400 missiles systems and its Bastion coastal defence system.
The Syrian conflict began when the Baath regime, in power since 1963 and led by Assad, responded with military force to peaceful protests demanding democratic reforms during the Arab Spring wave of uprisings, triggering an armed rebellion fuelled by mass defections from the Syrian army.
Russia has been operating a bombing campaign in Syria since 2015, when it stepped in to support Assad's rule and tipped the conflict in his favour. Human rights monitors say that the raids have resulted in many civilian casualties.
The brutal tactics pursued mainly by the regime, which have included the use of chemical weapons, sieges, mass executions and torture against civilians have led to war crimes investigations.