Updated March 21, 2022 at 2:18 AM ET

HELSINKI — The U.S. Marines have identified four of its servicemen who died when their Osprey aircraft crashed in Norway during a NATO exercise unrelated to the Ukraine war.

Those who died include Capt. Matthew J. Tomkiewicz, 27, of Fort Wayne, Indiana; Capt. Ross A. Reynolds, 27, of Leominster, Massachusetts; Gunnery Sgt. James W. Speedy, 30, of Cambridge, Ohio; and Cpl. Jacob M. Moore, 24, of Catlettsburg, Kentucky.

The men were in Norway for NATO's Cold Response 2022, which NATO described as "a long-planned exercise bringing together thousands of troops from NATO Allies and partners, testing their ability to work together in cold weather conditions across Norway – on land, in the air and at sea."

The four soldiers were retrieved from the crash site and are being transported back to the U.S. to be reunited with their families, Marines spokesperson Jacob M. Sugg said in a statement.

The cause of the crash is under investigation, but Norwegian police reported bad weather in the area.

"We will continue to execute the mission while keeping these Marines and their service on the forefront of our minds," said Maj. Gen. Michael Cederholm, the commanding general of 2d Marine Aircraft Wing, where the men served. "We will never allow these Marines' sacrifice to go unnoticed or unappreciated. Keep these Marines and their loved ones in your thoughts and prayers."

The aircraft was a MV-22B Osprey. It "had a crew of four and was out on a training mission in Nordland County" in northern Norway, the country's armed forces said in a statement.

It was on its way north to Bodoe, where it was scheduled to land just before 6 p.m. Friday. The Osprey crashed in Graetaedalen in Beiarn, south of Bodoe. Police said a search and rescue mission was launched immediately. At 1:30 a.m. Saturday, the police arrived at the scene and confirmed that the crew of four had died.

The Cold Response drill includes around 30,000 troops, 220 aircraft and 50 vessels from 27 countries. Non-NATO members Finland and Sweden are also participating. The exercises began on March 14 and end on April 1.

The Norwegian armed forces said that Cold Response "will carry on as planned, with the measures we have to take due to the weather."

The Associated Press reported that a Norwegian rescue helicopter spotted the crash site late Friday and local Red Cross crews were assigned to assist police on the ground, Norwegian media said.

Norwegian newspaper VG said Red Cross members drove close to the crash site with scooters and marked the trail with GPS for police in what they described as extremely difficult weather conditions early Saturday.

"It was a special night, it was a real storm. There were five of us driving towards the scene of the accident. There was one meter of visibility, snow and storm in the mountains, " Red Cross team leader Oerjan Kristensen told VG, according to the AP. "I guess it was a wind gust of 30-40 meters per second. When it blows like that, it is difficult to stand upright."

Kristensen added that the rescue operation is being hampered by the risk of landslides in the mountains, and the remoteness of the crash site.

The cause of the crash is being investigated

Police launched an investigation into the crash and accident commission members and police representatives were due to arrive at the crash site on Saturday.

"The weather is very bad in the area to complete work at the scene, but police will take it up again as soon as the weather conditions allow it," operations manager Ivar Bo Nilsson from the Norland police district told reporters, according to the AP.

Lt. Gen. Yngve Odlo, head of the Norwegian Armed Forces' operational headquarters, said that Cold Response would continue despite the crash.

"Right now there is full focus on ending the rescue operation, taking care of the people and then there will be a normal procedure with causation," Odlo was quoted as saying by Norwegian public broadcaster NRK.

The first Cold Response exercise was held in 2006, and the drills are conducted every two years. They take place in southeastern, central and northern Norway.

The Associated Press contributed to this report.

Copyright 2022 NPR. To see more, visit https://www.npr.org.