Despite the Kremlin's public defence of Syrian President Bashar al-Assad, including launching a military campaign to bolster his forces in the country's civil war, Russian President Vladimir Putin last year secretly asked the Middle Eastern leader to step down, the Financial Times reported on January 22.

Weeks before his death on January 3, Colonel-General Igor Sergun, the head of Russia's GRU military intelligence agency, was sent to Damascus to impart Putin's request and was angrily rebuffed, western intelligence sources told the newspaper.

The proposal delivered by Sergun, which would entail a choreographed transition of power to maintain the Alawite regime but clear the way for negotiations with moderate rebels, "added to a growing mood of optimism among Western intelligence agencies in late 2015", the paper wrote.

The long-term leader's exit would potentially remove the main obstacle to a multi-sided agreement to end the almost five-year conflict that has claimed some 250,000 lives, mainly civilians.

While Washington says Assad must go because of his indiscrimante use of heavy weapons in populated areas, Moscow says its ally's role was not negotiable. "Our position has not changed," Putin reiterated  in his year end press conference on December 17, 2015. "We believe only the Syrian people should decide who should govern them and in what conditions."

Behind the scenes, however, Moscow was increasingly unhappy with what it found since it launched its Syrian air campaign in late September.

"Mr Putin had taken a look under the bonnet of the Syrian regime,” one senior European intelligence official told the FT, "and found a lot more problems than he was bargaining for".

However, Russia overplayed its hand, the official said, and Mr Assad made clear to Sergun that there could be no future for Russia in Syria unless he remained as president. People close to the Syrian regime say suspicions about Russia's intentions have been growing in Damascus for some time.

"That mood of elation when Russia first got involved lasted for a while, but then people got more pessimistic," said one Damascus businessman. "Assad’s people started to realise that having the big brother defending them meant he could also demand things of them too."

Meanwhile, Assad has also been actively rooting out any powerful figures who could pose a challenge his leadership. A prime example was the disappearance of Abdelaziz al-Kheir, an Alawite dissident, Joshua Landis, a Syria analyst from Oklahoma State University, told the newspaper.

Al-Kheir, a leading member of the National Co-ordinating Body, a political grouping dedicated to negotiating with Assad to achieve democratic change, visited Moscow in 2012 and then Beijing.

"It seemed clear to everyone they were checking him out as a potential Alawite replacement to the current regime that could assure the Alawite community," Landis said. On his return to Damascus he was taken from the airport by security agencies. "That seemed to be a sign that Assad was not going to allow Russia to pick the next president."