The commandant of the US Marine Corps told around 300 Marines stationed in Norway they should prepare for a "bigass fight."
General Robert Neller told the Marine rotational force at the Norwegian Home Guard base near Trondheim: "I hope I'm wrong, but there's a war coming.
"You're in a fight here, an informational fight, a political fight, by your presence," he said, in comments reported by Military.com.
The general later said he expects the Pacific and Russia to be the focus of future conflicts outside of the Middle East.
"Just remember why you're here," Sergeant Major Ronald Green told the Marines, according to the military news site.
"They're watching. Just like you watch them, they watch you. We've got 300 Marines up here; we could go from 300 to 3,000 overnight. We could raise the bar."
The rotational force has been deployed in Norway since January, where they have supported Nato operations and trained in cold weather and mountainous conditions.
Tensions have been rising in the region since Russia annexed Crimea in March 2014.
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