Interfax also quoted a deputy Russian air force chief as saying that Russia will give the necessary protection to its citizens in Syria. "We must protect our citizens," Maj.-Gen. Vladimir Gradusov was quoted as saying. "We won't abandon the Russians and will evacuate them from the conflict zone, if necessary."

Asked whether the air force would provide air support for the navy squadron, Gradusov said they will act on orders.

The Defense Ministry had no immediate comment, and an official at the Black Sea fleet declined to comment.

Asked if the Pentagon is concerned about the plan, officials in Washington said it depends on the mission. They had no comment on the stated goal of protecting Russian citizens and the Russian military position there, something the U.S. would do in a foreign country if in a similar situation.

"I think we'd leave it to the Russian Ministry of Defense to speak to their naval movements and their national security decision-making process," said Capt.