Russia's role in helping Syrian forces recapture the ancient city of Palmyra has left the West scrambling to figure out President Vladimir Putin's game plan, following hopes he was edging away from supporting President Bashar al-Assad.

The seizure of the UNESCO World Heritage site on Sunday by forces fighting for Assad delivered the biggest blow so far to Islamic State jihadists and is a major coup both for Damascus and Moscow.

The military action comes after Putin announced he was withdrawing most of his forces from Syria, brokered with the United States a ceasefire in the country and raised Western hopes that Russia is edging away from its strong support for Assad.

"Russia is playing a decisive role in the (Palmyra) advance," said analyst Alexander Khramchikhin of the Institute of Political and Military Analysis in Moscow.

Russia's state media has highly publicised the return of planes from Syria after Putin's surprise withdrawal order on March 14, and on Monday showed soldiers loading three combat helicopters onto a Russia-bound cargo plane.

But analysts told AFP that the withdrawal has been very limited, with estimates ranging between 10 and 25 percent of Russia's forces in Syria.

- Special forces on ground -

Rather than spelling an end to Moscow's role in the conflict, the weeks since the military drawdown started have seen the Kremlin admit an even deeper involvement in the fighting.  
In the run up to the taking of Palmyra, Moscow openly admitted for the first time since it launched it operations in Syria last September that it has special forces on the ground as part of the offensive.

A special forces officer who was directing air strikes was earlier killed near Palmyra, the Russian military said Thursday, adding that he had been working there for just a week.

Armed forces chief Valery Gerasimov on Monday said Palmyra was "liberated thanks to the support of Russia's airforce and special operations forces".

An AFP correspondent saw Russian soldiers on the ground in Palmyra operating artillery, and a Syrian military source there said that the Russians are "widely involved in the battle for Palmyra, whether in fighting directly on the ground, with their planes, or by intercepting communications."

Moscow would be sending more soldiers in the coming days to help demine Palmyra, the Russian defence ministry said Monday.

- Switch in focus -

Russian military analyst Vladimir Yevseyev said that the month-old ceasefire hammered out by Putin and US President Barack Obama has allowed Moscow and Assad to refocus their attacks from moderate opposition groups to the jihadists.
 The truce "lets both the Russian airforce and Syrian army concentrate their power," Yevseyev told AFP.

"By concentrating their efforts in specific directions there can be a breakthrough, like in Palmyra," he said.

The commander of Russian forces in Syria, Alexander Dvornikov,  said last week that the capture of Palmyra would "open up the road to (IS strongholds) Raqa and Deir Ezzor and create conditions for reaching and taking control of the border with Iraq."

Syria's military on Sunday confirmed that a battle for Raqa -- the de-facto capital of IS jihadists -- is the plan.

And some analysts said that rather than hoping for Moscow to back away from Assad the West should get used to the idea that Moscow is going to back him for the long run.

"All the talk in the West that Russia was going to ditch Assad was nonsense," Pavel Felgengauer, a Russian military analyst who writes for opposition newspaper Novaya Gazeta, said.

"We are not planning to abandon him now. Russia wants Assad to stay in power and the goal is to give him a chance to win the civil war."