An RPG shell whistles towards its target, exploding in a ball of fire just as a group of soldiers in white fatigues, zip past on skis, bullets flying from their white rifles. It was all part of a training exercise by Russia's newly formed 80th Motor Rifle Arctic Brigade, which was established two years ago as part of the Kremlin's bid for dominance in the Arctic. The soldiers are trained to operate in some of the least hospitable climates in the world — where temperatures can drop to -40 — using tanks, military hardware and even reindeer sleds to get around in the frozen terrain.

More from NBC News: Deal on Government Funding Reached, Averting Shutdown Trump on North Korea's Kim Jong Un: 'He's a Pretty Smart Cookie' Pence: Tax Plan Could Increase Deficit 'Maybe in the Short Term' NBC News was granted rare access to the Alakurtti base this week, along with several other foreign media organizations. Located near the border with Finland in the Murmansk region, the Soviet-era base was refurbished and formally opened in 2015. Under President Vladimir Putin, Russia has launched the biggest military build-up in the Arctic since the fall of the USSR - bolstering its fleet of nuclear-fueled icebreakers, reopening abandoned Soviet military bases and building a string of new ones. Russia isn't alone in its Arctic ambition. The United States, Russia, Canada, Denmark, Norway and Iceland all lay claim to the area and its abundant natural resources. The U.S. Geological Survey estimates the Arctic may contain 13 percent of the world's undiscovered oil and 30 percent of its natural gas. And thanks to climate change, melting polar ice is expected to make drilling, mining and shipping even easier.

With billions of dollars in potential profits at stake, the race to control the region's riches is on. Russia is trying to claim 460,000 square miles of the Arctic Ocean as its national territory — an area that includes the North Pole. Russian divers even planted a national flag on the North Pole seabed in a symbolic claim to the region's energy riches. Washington is watching closely. Asked about Russia's military build-up in the Arctic at his confirmation hearing, U.S. Defense Secretary James Mattis said it was "not to our advantage to leave any part of the world" to others. American Marines have even been deployed to train for Arctic warfare in Norway.

In this photo taken on Tuesday, April 25, 2017, soldiers of the Arctic motorised rifle brigade of Russia's Northern Fleet took stand near APCs during military exercise in Alakyrtti, Murmansk region, Russia. Dmitry Kozlov | AP

Back at the Alakurtti base, soldiers demonstrated their hand-to-hand combat skills as journalists were herded from building to building, touring the canteen, the barracks and a brand-new medical facility. Russia insists it isn't looking for a confrontation. "The aim behind the creation of the brigade was to defend the interests and security of the Russian State in the Arctic," says Colonel Ilia Pavlovsky, Commander of 80th Motor Rifle Arctic Brigade. But with tensions between Washington and Moscow at an all-time low, the Arctic could become the coldest front line in a new faceoff between Russia and the West.