Despite the initial pullout, a monitoring group said Russian helicopters — and likely warplanes — which are still in Syria had pounded Islamic State group positions as regime troops pressed an advance.

UN peace envoy Staffan de Mistura described the withdrawal announcement as a “significant development” for negotiations that began in Geneva on Monday in the latest push to end the brutal conflict as it enters its sixth year.

“We hope (this) will have a positive impact on the progress of the negotiations,” he said in a statement.

President Vladimir Putin on Monday ordered the “main part” of Russia’s forces out of the war-torn nation, but the Kremlin denied it was trying to pressure its long-time ally President Bashar al-Assad.

Russia will, however, keep a contingent at its air and naval bases in Syria and a senior official said strikes against “terrorist targets” would continue.

Syrian Observatory for Human Rights director Rami Abdel Rahman told AFP that “Russian helicopters and warplanes, that are likely Russian” had struck IS targets around the ancient city of Palmyra. There was no official confirmation from Moscow.

Meanwhile, one Al-Qaeda linked group branded the withdrawal a “defeat” and vowed to launch a new offensive in Syria.

Putin said Monday that Moscow’s military goal had been “on the whole” completed some five-and-a-half months and 9,000 combat sorties after the Kremlin launched its bombing campaign in support of Assad.

State media broadcast live footage of flag-waving crowds and priests greeting returning pilots at a military base in southwest Russia as a brass band played.

– Dispute over Assad’s fate –

The West reacted cautiously to the announcement, since Moscow is yet to specify a timeframe for completing the withdrawal, and a Kremlin official said Russia will keep advanced air defence systems in Syria.

Some governments expressed hope the Russian move could push Assad to negotiate, but in Geneva both sides remained locked in a bitter dispute over his fate.

The talks opened after a temporary ceasefire between Assad’s forces and opponents went into force on February 27 and has largely held, although it does not cover IS jihadists and Al-Qaeda’s Syrian affiliate the Al-Nusra Front.

De Mistura was on Tuesday to hold his first official meeting with the opposition High Negotiations Committee (HNC), which has repeatedly said Assad cannot be part of Syria’s political future.

Damascus sparked Western anger by staking out an uncompromising stance before the talks, insisting that discussions on Assad’s removal were a “red line” they would not cross.

Putin’s spokesman Dmitry Peskov denied that the Kremlin was angered by Assad’s perceived inflexibility.

But in February, Russia was unusually critical of Assad after he vowed in an interview with AFP to retake the whole country, saying his stance was “not in accord” with Moscow’s diplomatic efforts.

German Foreign Minister Frank-Walter Steinmeier said a Russian withdrawal “increases the pressure” on Assad to negotiate, while France’s foreign ministry said “anything that helps towards a de-escalation in Syria should be encouraged”.

– Cautious assessment –

Moscow has pledged to ratchet up its own diplomatic efforts to find a political solution to a conflict that has killed more than 270,000 people and displaced millions since March 2011.

The White House said President Barack Obama had spoken to Putin following Russia’s announcement, and discussed the “next steps required to fully implement the cessation of hostilities”.

But US officials offered a cautious initial assessment.

“At this point, we are going to see how things play out over the next few days,” a senior administration official told AFP.

The foreign minister of Iran — which controls thousands of troops supporting Assad on the ground in Syria — said Russia’s withdrawal showed Moscow did not “see an imminent need (to) resort to force in maintaining the ceasefire”.

Russia began air strikes in Syria in September, in a move that helped shore up the regime’s crumbling forces and allowed them to go on the offensive.

Moscow sent some 50 warplanes to carry out thousands of strikes across Syria, saying it was targeting “terrorist” groups including IS jihadists.

The intervention was slammed by the West and its regional allies, which accused Moscow of mainly bombing more moderate rebels.

Meanwhile, a jihadist commander told AFP that Al-Nusra was preparing to launch a new offensive “within the next 48 hours”, saying the regime was unable to hold onto territory it had seized with the help of the Russians.

Syria’s main opposition welcomed the Kremlin announcement, but said it would wait to see what happens on the ground.

“We must verify the nature of this decision and its meaning,” HNC spokesman Salem al-Meslet told reporters in Geneva.

After his first official meeting with the regime on Monday, de Mistura told reporters that “strong statements (and) rhetoric” were part of every tough negotiation and that his initial discussions with government representative Bashar al-Jaafari were “useful”.

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