Russian warships, including the nuclear-powered submarine Kazan, have arrived in Cuba for military exercises.

The US nuclear-powered submarine USS Helena is in Guantanamo Bay for a routine visit.

The presence of the Kazan, part of Russia's new fleet, has raised concerns for the US military due to its nuclear capabilities.

The US Navy has deployed surveillance assets to monitor the situation.

Tensions are heightened by the history of Cuba's past alliance with the USSR during the Cold War.

Despite the proximity of Russian ships to US shores, authorities do not see an immediate threat from the deployment.