Cuba welcomes Russian military ships to Havana

A nuclear-powered submarine named Kazan is among the Russian vessels expected to remain through the weekend for a military drill in the Caribbean.

A US intelligence officer told CBS, BBC's North American partner, that the sub is not carrying nuclear weapons - despite its use of nuclear energy.

Cuba's Foreign Ministry identified the other Russian ships as the frigate Admiral Gorshkov, the fleet oil tanker Pashin and the salvage tug Nikolai Chiker.