The naval group, which also includes the Fotiy Krylov salvage tug and the Boris Butoma tanker left the Far Eastern port of Vladivostok for a month-long voyage on June 4.

"An official welcoming ceremony began at 0:00 Moscow time [20:00 GMT]," Capt. 1st Rank Roman Martov said.

Russia announced in 2007 that it was building up its naval presence across the world. Foreign port calls by Russian warships have become more frequent.

"The visit is to... further develop friendly relations between the fleets of Russia and the U.S.," a spokesman for the Pacific fleet said.

During the visit to San Francisco the Russian sailors will get acquainted with the city and its history, while San Francisco residents will be able to visit the ship, meet with the crew and listen to the music performed by the Pacific Fleet's orchestra

The Varyag is a Slava class missile cruiser, designed as a surface strike ship with some anti-air and ASW capability. The sixteen SS-N-12 Sandbox nuclear-capable supersonic anti-ship missiles are mounted in four pairs on either side of the superstructure, giving the ship a distinctive appearance.

NATO experts had dubbed Russian combat ships of this class "the killer of aircraft carriers," as it can launch 1,000 kg of high-explosives or a tactical nuclear warhead out to a range of 300 nautical miles.

In April 2009 the Varyag led a group of 21 foreign naval vessels participating in a parade to mark the 60th anniversary of China's Navy off the coast of the eastern city of Qingdao.

In November last year the flagship of the Pacific Fleet visited Singapore.