A U.S. Navy submarine has pulled into Guantanamo Bay, Cuba, in a show of force as a fleet of Russian warships gather for planned military exercises in the Caribbean.

A U.S. Navy submarine has arrived in Guantanamo Bay, Cuba, in a show of force as a fleet of Russian warships gather for planned military exercises in the Caribbean.

U.S. Southern Command said the USS Helena, a nuclear-powered fast attack submarine, pulled into the waters near the U.S. base in Cuba on Thursday, just a day after a Russian frigate, a nuclear-powered submarine, an oil tanker and a rescue tug crossed into Havana Bay after drills in the Atlantic Ocean.

The stop is part of a “routine port visit” as the submarine travels through Southern Command’s region, it said in a social media post.

Other U.S. ships also have been tracking and monitoring the Russian drills, which Pentagon officials say do not represent a threat to the United States.