Satellite pictures have emerged showing how Russian warships appear to have deserted a key naval base in Syria amid fears over possible US airstrikes.

Overhead Images show how at least 11 navy vessels, including the frigate Admiral Grigorovich, appear to have left the Tartus military port on the Syrian coast.

A picture, said to have been taken on Wednesday, shows how only a kilo-class submarine remains in the port, which is understood to be protected by Moscow's fearsome S-300 and S-400 missile defence systems.

It comes after Donald Trump told Russia to 'get ready' for missile strikes in Syria with the Kremlin having threatened to shoot down any rockets - and anything that launched them. Trump and his Western allies are considering action after a horrifying chemical attack on a Syrian rebel-held town killed at least 40.

The exact reason for the ships' movements is not yet clear, but some have speculated that the vessels are simply on a training exercise or that they may have been deployed in readiness to intercept missiles. 

It is not clear when the first of the images - produced by satellite imaging and intelligence firm ISI - was captured, but it is thought to have been taken before the poison gas attack on rebel-held Douma on Saturday.

Moscow was in direct contact with the US joint chiefs of staff about the situation in Syria, Vladimir Shamanov, head of the lower house of parliament's defense committee, said last night.

Yevgeny Serebrennikov, the first deputy chairman of the Russian upper house's defense committee, told Russian media that the Kremlin's troops in Syria were being protected.

He said: 'The Russian military bases in Hmeymim and Tartus are under firm protection.

'At the same time, we expect that in the event of US strikes, if any, the lives of our servicemen will not be in danger.

'I think that the United States understands this and will not allow it, because otherwise, Russia's response will be immediate.' 

As the threat of Western military action against the Syrian regime looms, Russia has already deployed thousands of troops in the war-torn country to back President Bashar al-Assad.

President Vladimir Putin first launched a military intervention in Syria in 2015, turning the tables in the multi-front civil war in favour of ally Assad.