The Norwegian government intends to add another 400 U.S. Marines to Norway before the most significant military exercise since the Cold War this fall, according to the country’s Ministry of Defense.

Currently, about 330 Marines from the 1st Battalion, 6th Marines (1/6), an infantry battalion in the U.S. Marine Corps based in Camp Lejeune, North Carolina, make up the rotational presence for training and exercise in the country. The influx of new Marines are expected to arrive from Romania and would increase the total number to 700 for a period of five years.

The new force of Marines will be situated in Setermoen, Norway, according to the Defense Ministry.

This fall, the North Atlantic Treaty Organization (NATO) will be leading a massive military exercise across the entire country of Norway, an unprecedented maneuver not seen since the days of the Cold War. It seems like Washington and Norway are making the preliminary adjustments before a total of 35,000 troops from 30 different countries kick off the exercise, called Trident Juncture.

Map detailing plans for upcoming military exercise:

Speaking at the Naval War College Tuesday, General Robert B. Neller said the approval for additional Marines in Norway cleared on Tuesday. Neller has been an advocate for sending Marines to extreme cold-weather environments for Arctic warfare training.

The government of #Norway has approved ~400 additional @USMC Marines to be posted in the at Setermoen in Troms, Norway. Norway shares a 122-mile border with Russia and the new location will be bring US Marines closer to that border. There are currently ~300 US Marines in Norway pic.twitter.com/bZ7duE9P7e — Artemis Moshtaghian (@ArtemisChats) June 12, 2018

The Marines are currently on six-month rotations to Norway, where soldiers are preparing for cold-weather warfare to counter Russia.

According to the map below, Norway shares a 122-mile border with Russia and the Setermoen region is roughly 250 miles from the border.

Norway’s defense minister Frank Bakke-Jensen had previously stated that his request for more US troops would come during the summer months.

“This is an important part of the NATO membership, to have allied troops [visiting] in Norway and training with us. So for us, it’s important, but we need to do some work on the numbers, on where they are supposed to exercise,” Bakke-Jensen previously said.

Pentagon spokesman Eric Pahon said the Department of Defense said the rotational training allows Marines to “take part in world-class winter and mountain warfare training,” which he said would “strengthen the US military’s bond with the Norwegian military, and build readiness to respond in times of crisis.”

“In times of crisis and war Norway will rely on US and other allied military reinforcements. This is at the core of Norwegian security policy and is further emphasized by our NATO-membership,” Norwegian Minister of Defence Frank Bakke-Jensen said in a statement provided to CNN. “The United States Marine Corps and Norway have a long-standing and successful relationship that we look forward to strengthening. We will continue the dialogue with the US and the USMC, aiming for mutual agreement in the near future on the continuation of the rotational training and exercise activity,” he added. “The initiative has proven that training and conducting exercises together with allies has had a positive impact on the operational capability of our own forces.”

NATO’s chess pieces are being positioned in Norway and surrounding regions before the largest military exercise since the Cold War this fall. How will Russia respond?