The official said the ships would carry an unspecified number of marines to protect Russians in Syria and evacuate some equipment from Tartus, if necessary.
Each ship is capable of carrying up to 300 marines and a dozen tanks, according to Russian media reports. That would make it the largest known Russian troop deployment to Syria, signaling that Moscow is becoming increasingly uneasy about Syria's slide toward civil war.
Interfax also quoted a deputy Russian air force chief as saying that Russia would give 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 it would 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 was concerned about the plan, officials in Washington said it depended on the mission. They had no comment on the stated goal of protecting Russian citizens and the Russian military position there, something the United States 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. John Kirby, a Pentagon spokesman, adding that it was not the business of the U.S. Defense Department to "endorse or disapprove of an internal mission like that."
What would greatly concern the United States, he said, is if the Russian naval ships were taking weapons or sending people to support the Assad regime in its crackdown.
"The secretary of defense (Leon Panetta) remains concerned about any efforts by external countries or external organizations to supply lethal arms to the Syrian regime so that they can turn around and use those to kill their own people," Kirby said.
Tartus is Russia's only naval base outside the former Soviet Union, serving Russian navy ships on missions to the Mediterranean and hosting an unspecified number of military personnel.