Syria's most powerful ally, Russia, said Thursday that President Bashar Assad is losing control of his country and the rebels might win the civil war, the first time Moscow has acknowledged the regime is cracking under the force of a powerful rebellion.

NATO also predicted Assad's fall, with Secretary-General Anders Fogh Rasmussen saying the regime's collapse is "only a matter of time."

"An opposition victory can't be excluded, unfortunately, but it's necessary to look at the facts: There is a trend for the government to progressively lose control over an increasing part of the territory," Russian Deputy Foreign Minister Mikhail Bogdanov said during hearings at a Kremlin advisory body.