Russia's decision to embark on a partial withdrawal from Syria is intended as a sharp rebuke to Syrian President Bashar al-Assad, who has increasingly wavered from Moscow's "script" for the conflict, according to U.S. intelligence officials.
Intelligence officials have said for months that Russian President Vladimir Putin was never wedded to the idea of Assad's leadership as a long-term solution in Syria, provided a suitable replacement could be found.
But recent comments by Assad, including some about wanting to retake all of Syria with Russia's help before negotiating a peace settlement, appear to have pushed Moscow too far.
"It is clear that Russia has grown frustrated by the intransigence and incompetence of the Syrian regime," a U.S. intelligence official told VOA on condition of anonymity.
"Putin may have propped up Assad in the short term, but he has also learned firsthand just how hollow the Syrian forces are," the official added. "It would not be a surprise to see Putin cut his losses and push Assad out."
So far, the move appears to have made some impact in Damascus, with a senior Assad adviser telling Russia's RIA news agency that the Russian military withdrawal was a natural step, while welcoming greater cooperation between the United States and Russia on peace talks.
"Russia is not writing a blank check," said Christopher Kozak, a research analyst at the Washington, D.C.-based Institute for the Study of War. "Russia expects a return on its investment and Assad needs to play ball right now while they have favorable conditions, in order to secure Russia's long-term interests."
Slow start to exit
But it also appears that Russia is not yet ready to cast Assad aside entirely.
Independent monitors and U.S. officials said Russia carried out airstrikes against the Islamic State terror group Tuesday in support of pro-regime forces in Palmyra. And U.S. defense officials said that, despite much fanfare, Russia's partial withdrawal is off to a slow start.
"We have seen some Russian aircraft depart Syria and return to Russia," Pentagon spokesman Peter Cook told reporters Tuesday, putting the number at "fewer than 10."
"We have to judge Russia by its actions, not its word, so we'll see," he added.
And even if Russia does quicken the pace of its military withdrawal from Syria, it still will maintain an airbase in Latakia province, as well as a presence at the key port of Tartous, allowing Putin to quickly ramp up Moscow's military presence.
"Putin is withdrawing the pieces of equipment that can be moved around very easily," said ISW's Kozak. "The infrastructure that's behind it, the air defense systems, like the S400 missile system, that's going to remain. So there are no startup costs in the future."