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Russia's continuing military buildup and ongoing airstrikes in Syria are raising concerns that President Obama is "flummoxed" by an intervention reminiscent, analysts say, of the incursion into eastern Ukraine.

“They are almost sibling interventions,” Joerg Forbrig, Transatlantic Fellow for Central and Eastern Europe at the German Marshall Fund of the United States, told FoxNews.com.

A senior Kremlin defense official told Russian media outlets this week that military veterans that had served in eastern Ukraine were likely to start fighting next in Syria as “volunteer” ground forces, according to The New York Times.

The announcement comes amid Russia’s escalating presence in the region, with the U.S. and NATO expressing concern over Russia’s fresh incursions into Turkish airspace.

Russia has said that its airstrikes are aimed against Islamic State forces, as well as Al Qaeda’s affiliates in Syria. However, U.S. officials have said that at least some of the strikes have hit Western-backed rebel factions fighting government troops, with the intention of protecting Syrian President Bashar al-Assad.

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    Speaking to reporters during a stop at Moron Air Base in Spain, Defense Secretary Ash Carter said he couldn't confirm reports there may be Russian volunteer soldiers in Syria, but warned against it.

    Russia Putin

    Oct. 6, 2015: Russian President Vladimir Putin listens during a meeting at the presidential residence in the Russian Black Sea Resort of Sochi, Russia (AP)

    "That would simply be deepening their mistake in Syria, if it's true," Carter said. "Those people are going to come under attack."

    Russian President Vladimir Putin appears to be pushing ahead with his Syria plans despite Obama administration efforts to de-escalate the situation and Obama claims that Putin is acting out of weakness. A senior U.S. official told Fox News last week that Obama and Putin earlier had agreed on a process to "deconflict" military operations, but the Russians "bypassed that process” when they launched airstrikes. The U.S. and Russia have since entered discussions again.

    The Russian incursion, and the subsequent response from Washington, has some analysts saying Washington has been caught flat-footed by the energy behind the Russian action.

    “Given that our response has been basically surprised bumbling I’m not terribly satisfied with [the response],” former Deputy Assistant Secretary of Defense Steven Bucci told FoxNews.com. “The Russians frankly caught them by surprise both by the deployment into Syria, the intelligence sharing with the Iraqis, the potential movement of ground troops and the aggression with which they are conducting operations. None of them have been responded to at all.”

    Bucci warned that relations with Sunni countries such as Jordan, Turkey and Saudi Arabia will be damaged by the U.S. apparently allowing Iran and Russia to take over operations in Syria. “They’re going to see it as at least by omission if not commission as the U.S. throwing in with the Shia collation against them, and I don’t think they're going to be all that happy about it. I’m concerned they’re going to take it into their own hands. The whole thing kind of looks like Europe before World War I,” Bucci said.

    The escalating geopolitical situation, the shadowy use of ground troops and the lack of significant response from Washington has some drawing parallels to Russia’s advance into eastern Ukraine after the fall of Ukraine President Viktor Yanukovych in 2014.

    “In both cases Mr. Putin has acted with unexpected vigor,” former U.S. ambassador to Ukraine John Herbst told FoxNews.com. “It’s clear Washington was flummoxed when Putin took Crimea and went into eastern Ukraine. It appears they’ve been flummoxed by Putin entering Syria.”

    'Teddy Roosevelt said to walk softly and carry a big stick – unfortunately Mr. Obama seems to have inverted that.'

    — Former U.S. ambassador to Ukraine John Herbst

    Herbst said that the Obama administration needs to respond forcefully to Moscow’s advances, which would in turn send a strong warning to America’s enemies, and a reassuring message to its allies in the region. “Under Obama we have not made it clear that it is a mistake to trifle with the U.S. If we don’t respond it makes us look weak. Teddy Roosevelt said to walk softly and carry a big stick – unfortunately Mr. Obama seems to have inverted that.”

    Forbrig said, “The overriding motive here is that Russia pushes its way into a situation not to occupy a country … but to have a say in the future handling or settling of the conflict."

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    While he called for a stronger stance against Russia, Bucci said there may not be many good options left to the administration.

    “At this point I don’t think there is a good answer or one that the administration would consider. Regardless of who is in the White House, once you’ve let it get to this point, your options are limited and none of them are terribly palatable,” Bucci said.

    However, White House Press Secretary Josh Earnest told reporters Tuesday that it was Russia making the tactical missteps:

    "I don't think President Putin is playing chess, he's playing checkers ... by making the tactical decision to ramp up their support for the Assad regime, Russia is being sucked into a sectarian civil war, essentially a quagmire, that poses a whole set of risks to Russia's interests not just in the region, but back at home."

    Fox News’ Jennifer Griffin, Lucas Tomlinson and The Associated Press contributed to this report.