Russia will be sending an anti-submarine ship and a missile cruiser to the Mediterranean "over the next few days" as the West prepares for possible strikes against Syria, the Interfax news agency says.

"The well-known situation shaping up in the eastern Mediterranean called for certain corrections to the make-up of the naval forces," a source in the Russian general staff told Interfax.

"A large anti-submarine ship of the Northern Fleet will join them (the existing naval forces) over the next few days.

"Later it will be joined by the Moskva, a rocket cruiser of the Black Sea Fleet which is now wrapping up its tasks in the northern Atlantic and will soon begin a Transatlantic voyage towards the Strait of Gibraltar."