Russian navy ships have been spotted leaving the Kremlin’s crucial seaport in the Mediterranean as the renewed Syrian civil war threatens to engulf it.

Naval analyst H I Sutton said Russia’s Tartus naval base in Syria was now under threat from rebel attack as the fast-moving front line closed in.

“The dramatic shift in the front lines in Syria now puts the base at risk. There are indications that Russia may be evacuating its naval vessels,” he said.

The Tartus naval base is important for Russia because it is its only Mediterranean “replenishment and repair point”. It has also been used as the dropping-off point for Russian special forces to enter the Syrian conflict.

So important is Tartus to the Russian navy that in 2017, Putin ordered its expansion.

But H I Sutton said two of Russia’s five naval ships had now left the port. Russia also has a submarine based at Tartus.

This “is the first visible sign that Russia is moving valuable assets out of the country,” he said.