The Pentagon has rejected Russian insinuations that U.S. forces were involved in recent drone attacks against Russia's air base and its naval facility in western Syria.
Spokesman Marine Major Adrian Rankine-Galloway said on January 9 that "any suggestion that U.S. or coalition forces played a role in an attack on a Russian base is without any basis in fact and is utterly irresponsible."
The comments come after Russia's Defense Ministry noted in a statement the "strange coincidence" of a U.S. military intelligence plane flying over the Mediterranean near the Hmeimim air base and Tartus naval facility at the moment of the attacks.
"Hardly anyone could have obtained the exact coordinates [for the attacks] based on space-based reconnaissance," it also said.
The statement came a day after the Defense Ministry said that 13 armed drones were used to attack its facilities in Hmeimim and Tartus overnight on January 5-6.
The ministry said seven of the unmanned aerial vehicles were shot down and the six others were forced to land without inflicting any casualties or damage.
A monitoring group, the British-based Syrian Observatory for Human Rights, said the attacks were carried out by an Islamist rebel faction that operates in Latakia Province, where the Hmeimim base is located, according to the Associated Press news agency.
Russia has given President Bashar al-Assad's government crucial support throughout Syria's civil war and has long been at odds with U.S. support of certain rebel groups in the Syrian civil war.
The conflict has killed hundreds of thousands of people and driven millions from their homes since it began with a crackdown on pro-democracy protests in 2011.
More than 40 Russian military personnel died in Syria since Moscow launched a campaign of air strikes in September 2015, in many cases using Hmeimim as a base.
During a visit to the air base on December 11, Russian President Vladimir Putin declared victory over "the most combat-capable international terrorist group" -- a reference to the extremist group Islamic State (IS) -- and announced a partial withdrawal of Russian troops.
'All Necessary Means'
Western officials say that the Russian campaign, particularly in its earlier stages, focused heavily on targeting rebels seeking Assad's ouster rather than IS militants.
Asked whether the announcement of a partial withdrawal could have been premature, Putin's spokesman Dmitry Peskov said on January 9 that the Russian forces in Syria have "all the necessary means" to counter any challenge.
Putin said on December 28 that more than 48,000 Russian military personnel had served in the operation in Syria, and that Russia's presence at Hmeimim and Tartus would be "permanent."
On December 29, Putin signed a law ratifying an agreement enabling Russia to expand operations at its naval facility in Tartus.