MOSCOW (Reuters) - President Vladimir Putin said on Thursday that Russia could scale up its military presence in Syria again within hours and would still bomb terrorist groups there despite a partial draw-down of forces ordered after military successes.

Speaking in one of the Kremlin’s grandest halls three days after he ordered Russian forces to partially withdraw from Syria, the Russian leader said the smaller strike force he had left behind was big enough to help forces loyal to President Bashar al-Assad keep advancing.

“I’m sure that we will see new and serious successes in the near future,” Putin told an audience of more than 700 members of the military at an awards ceremony. In particular, he said he hoped that the ancient city of Palmyra, which is held by Islamic State, would soon fall to Assad’s forces.

“I hope that this pearl of world civilization, or at least what’s left of it after bandits have held sway there, will be returned to the Syrian people and the entire world,” Putin said, referring to the World Heritage Site.

In his first public remarks since ordering the withdrawal, Putin for the first time put an approximate price tag on the Russian operation, saying that the bulk of the expenses - 33 billion rubles ($481.89 million) - had been taken from the defense ministry’s war games budget.

There would be other costs, he said, in order to replace ammunition and weapons as well as to make repairs.

Russian air strikes against Islamic State, Al Nusra and other terrorist groups would press on, he said, as would a wide range of measures to aid Syrian government forces including helping them plan their offensives.

Putin said he did not want to have to escalate Russia’s involvement in the conflict again after the draw-down and was hoping peace talks would be successful. But he made clear Russia could easily scale up its forces again.

“If necessary, literally within a few hours, Russia can build up its contingent in the region to a size proportionate to the situation developing there and use the entire arsenal of capabilities at our disposal,” he said.

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A senior Obama administration official said that the United States has monitored the return to Russia of a “substantial number” of fixed-wing aircraft and confirmed Putin’s assertion that the they could fly back to Syria within hours.

But Russian helicopters, armor, long-range rocket batteries and most of the estimated 5,000 Russian personnel appear to have remained in Syria, said the official, who requested anonymity in order to discuss the sensitive matter.

A Russian military source has told the Interfax news agency that only around 1,000 troops would stay, of whom more than half would be military advisers.

“THIS PATHWAY TO PEACE”

In a thinly disguised warning to Turkey and others, he said Russia was leaving behind its most advanced S-400 air defense system and would not hesitate to shoot down “any target” which violated Syrian air space.

Unexpectedly, he also paid tribute to a Russian soldier whose death in the five-month operation had previously been unacknowledged. By doing so, Putin tacitly raised the death toll for Russian servicemen to five and confirmed that special forces had been deployed.

Dampening speculation of a rift between Moscow and Damascus over the draw-down, he said the pullout was agreed with Assad beforehand and that the Syrian leader had backed the decision.

Still, the drawdown gives Putin considerable leverage over Assad. Russia could threaten not to send the aircraft back to protect government forces if the Syrian leader continues attacks on moderate opposition forces, said the Obama administration official.

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Praising Assad for “his restraint, sincere desire for peace and for his readiness for compromise and dialogue”, Putin said the Russian demarche had sent a positive signal for all sides taking part in peace talks in Geneva.

“You, soldiers of Russia, opened up this pathway to peace,” he told the audience.

Russia took the world by surprise by first launching air strikes on Sept. 30 last year. The sudden announcement of a partial withdrawal of forces was also unexpected.

Moscow will finish pulling out most of its strike force “any day now” and no later than by the end of this week, Viktor Bondarev, the head of the Russian air force, told the Komsomolskaya Pravda paper in an interview published on Thursday.

That tallies with an updated Reuters calculation based on state TV and other footage, which shows that as of Thursday 18 or half of Russia’s estimated 36 fixed-wing warplanes had flown out of Syria in the past three days.

Mikhail Barabanov, a senior research fellow at the Moscow-based Centre for Analysis of Strategies and Technologies, said the swift withdrawal was meant to show the world how fleet-footed the Russian air force had become in recent years.

($1 = 68.4800 rubles)