HELSINKI (AP) -- NATO kicked off nearly a two-week U.S.-led naval exercise on the Baltic Sea on Sunday with more than 7,000 sailors, airmen and marines from 16 nations, including two aspiring to join the military alliance, Finland and Sweden.
The annual BALTOPS naval exercise, initiated in 1972, is not held in response to any specific threat. But the military alliance said that "with both Sweden and Finland participating, NATO is seizing the chance in an unpredictable world to enhance its joint force resilience and strength" together with two Nordic aspirant nations.
Finland and Sweden both have a long history of military non-alignment before their governments decided to apply to join NATO in May, a direct result of Russia's Feb. 24 invasion of Ukraine. Over the past years, Moscow has repeatedly warned Helsinki and Stockholm against joining the Western military alliance and warned of retaliatory measures if they did.
Ahead of the naval drill, which involved 45 vessels and 75 aircraft, the top U.S military official said in Sweden -- the host of the BALTOPS 22 exercise -- that it was particularly important for NATO to show support to the governments in Helsinki and Stockholm.
"It is important for us, the United States, and the other NATO countries to show solidarity with both Finland and Sweden in this exercise," U.S. Gen. Mark Milley, Chairman of the Joint Chiefs of Staff, said Saturday during a news conference aboard the large amphibious warship USS Kearsarge, which was moored in central Stockholm.
Milley, speaking with the Swedish Prime Minister Magdalena Andersson, stressed that the Baltic Sea is a strategically important body of water -- "one of the great seaways of the world."
He said from Moscow's perspective, Finland and Sweden joining NATO will be "very problematic" and leave Russia in a difficult military position as the Baltic Sea's coastline would be almost completely encircled by NATO members, except for Russia's Baltic exclave of Kaliningrad and the Russian city of St. Petersburg and its surrounding areas.
Turkey, a NATO member that has had good relations with Russia, has objected to Finland and Sweden joining the military alliance, citing their alleged support for a Kurdish group that Turkey labels as terrorist. NATO's chief has been trying to resolve the dispute.
The United States has never before moved such a large warship as the 843-foot USS Kearsarge in the Swedish capital, where it sailed through narrow passages in the Stockholm archipelago, Milley said.
As NATO's close partners, Finland and Sweden have participated in the naval drill since the mid-1990s.
BALTOPS 22 is scheduled to end in the German port of Kiel on June 17.