Russia is to pull its forces out of Syria and focus on brokering a peace deal to end the civil war, President Vladimir Putin said today.
In what could herald yet another major shift in Syria's conflict, Putin said he was instructing his armed forces to end their five month campaign in support of President Bashar al-Assad's regime.
The announcement came ahead of the widely-anticipated five year anniversary of the war.
Speaking at a meeting in the Kremlin with his defence and foreign ministers, Putin said that the Russian military had "fulfilled" their objectives in Syria and that Moscow would now focus on diplomatic efforts to forge peace.
"I believe that the task put before the defence ministry and Russian armed forces has, on the whole, been fulfilled," he said.
"With the participation of the Russian military... the Syrian armed forces and patriotic Syrian forces have been able to achieve a fundamental turnaround in the fight against international terrorism and have taken the initiative in almost all respects.
"I am therefore ordering the defence minister, from tomorrow, to start the withdrawal of the main part of our military contingent from the Syrian Arab Republic."
Putin did not give a timeline for the withdrawal, and said that Russian forces would stay on at the port of Tartou, where the Kremlin has an existing military base, and at the Hmeymim airbase in Syria's Latakia province.
A Kremlin spokesman said that Assad had been informed by Putin of the Russian decision by phone.
The move was announced on the day United Nations-brokered talks between the warring sides in Syria resumed in Geneva.
Putin's claim to have created "the conditions for the start of the peace process" will be disputed by Western governments, who claim Russia's decision to enter the war has made the conflict even worse than it was.
While the Kremlin claimed to be aiming its bombers at "terrorists" fighting President Assad, critics say that the vast majority of Russian bombing raids have been targeted on Syria's mainstream rebel opposition, much of which the West supports.
Britain and other Western nations claim that hardly any of the Russian raids have targeted bases or assets of the Islamic State, which is now the West's main security concern in Syria.
The Russian force in Syria has been estimated to number some 4000 men, including airmen, logistical support, and marine infantry. While the Kremlin has not acknowledged it, there is also evidence that Russian artillery units have been active in the campaign.
The West and human rights groups have accused Russia of killing hundreds of civilians in its air raids, including the bombing of several hospitals.
The US offered no immediate reaction to Putin's announcement and analysts said it was too soon to say what impact the decision would have.
"The question now is how long the withdrawal will take and what does Putin means by 'the main component' of Russia's military in Syria? If he doesn't mean the aerial component, and if the withdrawal takes months, this won't mean anything," said Michael Horowitz, a security analyst with the Levantine Group.
The move could give fresh impetus to the UN-brokered peace talks in Geneva, which began after the unexpected success of a ceasefire agreement that went into force last month.
Although there has been sporadic fighting since the truce began on February 26, the level of violence has fallen dramatically in Syria in the last three weeks.
The truce does not include Isil or the al-Nusra Front, an al-Qaeda group in Syria, and the US, Britain and other coalition countries have continued bombing Isil forces.
Huge gulfs remain the opposition and the regime at the peace talks, including on the issue of a "political transition" in Syria.
The opposition demands that the transition include the immediate removal of Mr Assad, while the regime says it is limited to creating a new constitution and elections in which he would be allowed to stand.
Meanwhile, the UN released new figures showing that the Syrian civil war has turned 2.4 million children into refugees.
The numbers were released by the United Nations children's fund Unicef and a host of other agencies to mark five years since the first protests against the Assad regime began in 2011, triggering a wider uprising.
Tens of thousands of children are among the quarter of a million dead.
Children - including girls and many under-15s are being recruited as soldiers. Among the worst hit were those suffering from the latest tactic of imposing sieges on civilian areas, who were starting to die of starvation.