US Secretary of State John Kerry with Russian Foreign Minister Sergei Lavrov at a news conference after their meeting in Geneva on September 9. Kevin Lamarque/Reuters Russia deployed S-300 surface-to-air missiles to Syria's western coast on Tuesday in a move apparently aimed at preempting possible US airstrikes on Syrian army positions.

The move came in response to reports published earlier this week that Washington was considering targeting forces loyal to Syrian President Bashar Assad, and it was followed closely by a thinly veiled threat that the missiles' radius could be "a surprise" to all unidentified flying objects operating in Syria.

"Any missile or airstrikes on the territory controlled by the Syrian government will create a clear threat to Russian servicemen," Gen. Igor Konashenkov, a Russian Defense Ministry spokesman, said in a statement released on Thursday.

He also suggested the Russians would fire on any aircraft taking offensive action near Russian troops even before identifying them, leaving open the possibility that Russia would attack US aircraft.

"Russian air defense system crews are unlikely to have time to determine in a 'straight line' the exact flight paths of missiles and then who the warheads belong to," the statement read. "And all the illusions of amateurs about the existence of 'invisible' jets will face a disappointing reality."

The statement came three days after the US formally suspended its talks with Russia over Syria and a day after White House press secretary Josh Earnest questioned "Russia's credibility and intentions inside of Syria."

The US-based Russian embassy tweeted in response to Earnest's comment that "Russia will take every defensive measure necessary to protect its personnel stationed in Syria from terrorist threat."

The warnings are mainly a response to reports from earlier this week that the US officials were floating plans to launch limited airstrikes against Syrian regime positions.

"History shows that often such reports are the prologue to real action," the statement read.

Konashenkov said of "particular concern" was information that "the initiators of such provocations are representatives of the CIA and the Pentagon," who "today are lobbying for 'kinetic' scenarios in Syria."

He was apparently referring to a report in The Washington Post published on Tuesday that Russia's latest scorched-earth government offensive on Aleppo, which has killed hundreds of civilians and opposition fighters in the city's rebel-held east over the past two weeks, has spawned an "increased mood in support of kinetic actions against the regime."

"The CIA and the Joint Staff have said that the fall of Aleppo would undermine America's counterterrorism goals in Syria," a senior administration official told The Post.

Russian Foreign Minister Sergei Lavrov later said in a press conference with French Foreign Minister Jean-Marc Ayrault that the missile systems were purely defensive and posed no threat to anyone, Reuters reported.

Still, some observers were quick to point out that Konashenkov's statements amounted to a warning that Russia was prepared to shoot down US warplanes operating in Syria if they target pro-Assad forces.

"Russia just said it will shoot down any missile or jet attacking the Syrian army; without waiting to identify it," Russia Today reporter Murad Gazdiev tweeted.

"Just got a statement from Russian Ministry of Defense that basically says Russia would shoot down coalition jets if US launches airstrikes against Assad," Roland Oliphant, a Moscow correspondent for The Telegraph, added on Twitter.

And Nadav Pollak, a former senior fellow at the Washington Institute who is a counterterrorism analyst at the Anti-Defamation League, said: "Russia is basically saying: 'If we take down a coalition jet fighter, it's your fault.' Very aggressive rhetoric."

Russia accused the US of "blatant aggression" after US warplanes targeted a Syrian army base on Al-Tharda mountain on September 17, killing as many as 80 Syrian troops. The Obama administration said the airstrike was meant to target the Islamic State.

"I point out to all the 'hotheads' that following the September 17 coalition airstrike on the Syrian Army in Deir ez-Zor, we took all necessary measures to exclude any similar 'accidents' happening to Russian forces in Syria," Konashenkov said.