The submarine Kazan, which Cuba says is not carrying nuclear weapons, was accompanied by the frigate Admiral Gorshkov, as well as an oil tanker and a salvage tug.

The Kazan and Admiral Gorshkov, which is one of Russia's most modern warships, could be seen just off Havana, which is about 90 miles (145 km) from the tip of Florida.

The tanker Pashin and the tug, flying the white, blue and red tricolor of Russia, entered the harbor early Wednesday morning, an AFP reporter said.

The Cuban government announced that Foreign Minister Bruno Rodriguez was meeting his Russian counterpart Sergei Lavrov in Moscow on Wednesday, as the two former Cold War allies further tighten their links.

The unusual deployment of the Russian military so close to the United States -- particularly the powerful submarine -- comes amid major tensions over the war in Ukraine, where the Western-backed government is fighting a Russian invasion.

Cuban President Miguel Diaz-Canel met with Russian counterpart Vladimir Putin last month for the annual May 9 military parade on Red Square outside the Kremlin.

During the Cold War, Cuba was an important client state for the Soviet Union. The deployment of Soviet nuclear missile sites on the island triggered the Cuban Missile Crisis of 1962, when Washington and Moscow came close to war.

Relations between Russia and Cuba have become closer since a 2022 meeting between Diaz-Canel and Putin.