A US 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.

US Southern Command said the USS Helena, a nuclear-powered fast attack submarine, pulled into the waters near the US 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 US ships also have been tracking the Russian drills.

“This is not a surprise. We’ve seen them do these type of port calls before,” Pentagon spokeswoman Sabrina Singh said on Wednesday when asked about the Russian drills. “We of course take it seriously, but these exercises don’t pose a threat to the United States.”

The exercises come less than 2 weeks after President Joe Biden authorised Ukraine to use US-provided weapons.