American and Canadian warships tracked a Russian submarine as it travelled along the Florida coast, the U.S. Navy has said.

A Russian naval flotilla that docked in Havana, Cuba, last week raised concerns over Moscow’s intentions in the western hemisphere.

An unnamed U.S. official told the Miami Herald that Russia had split up the flotilla and sent its nuclear submarine north to the Atlantic, and the rest of its warships south, where they are likely to dock in Venezuela.

U.S. and Canadian warships, including destroyers and Coast Guard cutters, followed the submarine as it headed up the Florida coast in international waters.

An official from U.S. Northern Command told the Miami Herald that the U.S. Navy “continues to closely monitor” the Russian vessel’s movements.

This is a breaking story. More to follow.