Story highlights Syria's al-Assad faces mounting odds as the revolt against him drags on, Medvedev says

The Syrian leader's resistance to reform is an "important, if not fatal" mistake, he says

But Medvedev says Syrians, not outside powers, should choose the country's new leaders

Syrian President Bashar al-Assad's odds of holding power "are slipping away" as the nearly 2-year-old revolt against his rule grinds on, Russian Prime Minister Dmitry Medvedev says.

In an interview that aired Sunday on CNN's "Fareed Zakaria GPS," Medvedev distanced Moscow from its longtime Middle East client. But he repeated Russia's longtime insistence that outside powers shouldn't be picking Syria's leaders.

"From the outset, the Russian Federation was not an exclusive ally of Syria or President Assad," Medvedev said. "We used to have good relations with him and his father, but he had much closer allies among the Europeans."

Russia has "never said that our goal was to preserve the current political regime, or making sure that President Assad stays in power," he added. "That decision has to be made by the Syrian people."

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It's the latest in a series of grim assessments of al-Assad's chances from Russia, which has been Syria's leading arms supplier since the days of the Cold War. President Vladimir Putin said in December that Moscow won't support al-Assad "at any cost," and Deputy Foreign Minister Mikhail Bogdanov noted a few days earlier that the Kremlin "can't exclude a victory by the opposition."

When the Arab Spring revolts erupted across the region in early 2011, Syrians took to the streets to demonstrate against al-Assad's rule. The Syrian leader quickly responded with a crackdown by police and the army that soon exploded into a civil war. The United Nations says the conflict has now killed more than 60,000 people, and opposition activists said more than 100 were killed Sunday.

Rebel forces -- many of them led by former soldiers, others by jihadists linked to the al Qaeda terrorist network -- are now regularly battling government troops in the capital, Damascus, and the country's commercial hub of Aleppo.

Medvedev said he blames both the opposition and al-Assad's government for refusing to negotiate. He said he personally lobbied al-Assad to open up his regime to reform and that his resistance was an "important, if not fatal" mistake.

"The chances for him surviving are slipping away as days and weeks go by," Medvedev told CNN. "But once again, it should not be up to us. It should be up to the Syrian people."

Russia has criticized Western powers , including the United States, that have recognized the opposition as Syria's rightful leadership. Russia and China have blocked U.N. Security Council attempts to take action to end the conflict and force al-Assad to step down.

Medvedev spoke to CNN at the World Economic Forum in Davos, Switzerland. His comments contrasted with those of Jordan's King Abdullah II , who said Friday that al-Assad is not likely to fall for months.

"Anyone who says that Bashar's regime has got weeks to live really doesn't know the reality on the ground," he said during a panel appearance with Zakaria at the World Economic Forum. "They still have capability. ... So (I expect) a strong showing for at least the first half of 2013."

But Medvedev warned that if al-Assad's rule is "swept away" by the revolt, the result could be a conflict among its successors that could last "for decades." Asked about concerns that jihadists could use a successful campaign in Syria to spread into southern Russia, where Islamic militant groups have been battling Moscow for more than a decade, he said that prospect should alarm the West as well.

"They can travel to Europe. They tried to. And in the U.S.," Medvedev said. "So it is alarming for all of us. It does not mean, though, that we should bring to power radical opposition leaders. It should be a difficult process, led by civil society."