Russia is sending armed troops to Syria amid escalating violence there, United States military officials told NBC News Friday, in a move certain to frustrate Western efforts to put pressure on the regime of President Bashir Assad.
Moscow has sent a ship carrying a small contingent of combat forces to guard Russias deep-water port and military base at the Syrian city of Tartus, the US officials said.
The U.S. officials also said Russia has not sent additional attack helicopters to the Syrian government, but replacement parts for the Russian helicopters the Syrians are already flying.
It comes after the conflict was declared by France on Wednesday to be a full-blown civil war.
The head of the U.N. observers in Syria said Friday a recent spike in bloodshed is derailing the mission to monitor and defuse more than a year of violence and could prompt the unarmed force to pull out.
"Violence over the past 10 days has been intensifying willingly by the both parties, with losses on both sides and significant risks to our observers," Maj. Gen. Robert Mood told reporters in Damascus. "The escalating violence is now limiting our ability to observe, verify, report as well as assist in local dialogue and stability projects."
Tartus is one of Russias most strategically-important assets, giving it military access to the Mediterranean Sea.
Russia and China, both permanent members of the U.N. Security Council with veto power, frustrated attempts by key Western figures, including Secretary of State Hillary Clinton, to enforce a United Nations peace plan brokered by special envoy Kofi Annan.
Russias foreign minister Sergei Lavrov on Friday repeated Moscow's strong opposition to external interference in Syria, said it was not discussing plans for a Syrian political transformation following the exit of Assad.
PhotoBlog: Inside Syria
At a news conference after talks with his Iraqi counterpart, Lavrov said he had seen reports saying U.S. State Department spokeswoman Victoria Nuland had suggested Washington and Moscow were discussing a post-Assad strategy in Syria.
"If that was really said then it's not true," Lavrov said. "Such discussions are not being held and cannot be held, because to decide for the Syrian people contradicts our position completely.
"We do not get involved in overthrowing regimes - neither through approval of unilateral actions by the U.N. Security Council nor by participation in any political plots."
Nuland was asked at a news conference on Thursday whether the United States and Russia were discussing a transition of power similar to that seen in Yemen last year, in which President Ali Abdullah Saleh was replaced by a deputy.
"We are continuing to talk about a post-Assad transition strategy in that context," she said.