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MOSCOW - A top Russian official for the first time suggested that Syrian President Bashar Assad's grip on power may be slipping.

"We must look at the facts. There is a trend for the government to progressively lose control over an increasing part of the territory," Deputy Foreign Minister Mikhail Bogdanov said today. He added, "An opposition victory cannot be excluded."

His comments may signal a new calculation by the Kremlin that even its support for the Assad government may not be enough to sustain Assad's control. Bogdanov, however, also hedged his comments saying a rebel military victory will only come after many more deaths.

"If such a price for the ouster of the president seems acceptable to you, what can we do? We, of course, consider it absolutely unacceptable," he said, according to the Associated Press.

Syria at War

Moscow is one of Assad's few remaining allies. The Assad government is a major Russian arms client and allows the Russian Navy to maintain a ramshackle, yet strategic refueling base in its Mediterranean port of Tartus. The Russian government has repeatedly opposed international interference in the conflict and has been reluctant to use its influence to convince Assad to leave the country. Instead, Russia has deferred to international mediators who have so far failed to resolve the conflict.

Last week Russian Foreign Minister Sergei Lavrov met with Secretary of State Hillary Clinton to discuss the situation in Syria. The United States has called on Russia to use its leverage to convince Assad to give up the fight and leave the country. A senior U.S. official, however, tells ABC News that the Russians do not envy that position because they fear they may not be able to convince Assad to flee even if they tried.

This week President Obama announced that the United States now recognizes the Syrian rebels as the legitimate representatives of the Syrian people. Lavrov said he was surprised by the announcement, calling it "unexpected" and suggesting it shows the United States is more interested in a rebel military victory than a negotiated peace settlement.

In his comments today, Deputy Foreign Minister Bogdanov also expressed concerns that Syria's chemical weapons could fall into terrorist hands.

"This has already happened in Aleppo with the seizure of a plant manufacturing chemical components that can be used for terrorist purposes," he said, according to RIA Novosti, which also reports that Syrian officials have assured Russia they have no plans to use chemical weapons.

The Associated Press contributed to this report.