NATO is holding an annual naval exercise on the Baltic Sea along with Sweden and Finland, which applied for membership to the Western military alliance last month.
Fourteen NATO member countries, including the United States, Germany and Turkey, are taking part in the two-week exercise that began on Sunday.
NATO says the naval drill is aimed at strengthening response capabilities needed to protect freedom and safety of navigation across the Baltic Sea.
On Tuesday, US forces conducted landing practice on the Swedish island of Gotland. Minesweeping drills, as well as a mock battle in anticipation of an attack by enemy submarines, are also planned.
NATO says the naval exercise has been held annually for the past 50 years and is not directly related to Russia's invasion of Ukraine.
US Joint Chiefs of Staff Chairman General Mark Milley spoke about the exercise at a news conference in Stockholm on Saturday. He said the US is committed to a common cause, a rules-based international order and the idea that large countries can't invade small countries at no cost.