The American military is going to deploy rotations of US-based armored brigade combat teams and new equipment on NATO's eastern borders in response to an "aggressive Russia."

A brigade's worth of soldiers — around 4,500 soldiers each — will be on nine-month rotations in the region starting in February 2017 — the first such deployment since the end of the Cold War.

They will conduct military exercises across Estonia, Latvia, Lithuania, Poland, Romania, Bulgaria, and Hungary, according to a statement from US European Command.

A host of new heavy equipment including 250 tanks, Bradley Fighting Vehicles, Paladin self-propelled howitzers, and more than 1,700 additional wheeled vehicles and trucks will also be sent, reported the Wall Street Journal (WSJ).

The extra troops' presence in Europe will be continuous and bring the total US Army presence on the continent to three fully manned brigades, the military said.

The US has around 62,000 military personnel permanently stationed in Europe across 21 bases, and has previously sent a brigade in intermittently.

Deputy Secretary of Defense Robert Work told the WSJ that the extra troops and gear, combined with what the US already had in Europe, meant "there will be a division's worth of stuff to fight if something happens. If push came to shove, they'd be able to come together as a cohesive unit that has trained together, with all their organic equipment, and fight. That's a whole lot better than what we have right now," he said.

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The decision means US allies will "see a more frequent presence of an armored brigade with more modernized equipment in their countries," said General Philip Breedlove, commander of US European Command.

The Pentagon last month proposed quadrupling its budget for European defense to counter what it sees as a growing Russian threat.

It has budgeted to sharply boost military training and exercises aimed at reassuring European countries concerned about Russia, which seized Ukraine's Crimean peninsula in 2014 and has worried NATO allies with its strategic bomber flights.

Current equipment used in Europe will be upgraded and stored in Belgium, the Netherlands, and Germany, and will allow for "additional combat power, if and when needed," the military said.

"We're taking a strong and balanced approach to deter Russian aggression," said Defense Secretary Ash Carter during a speech at the Economic Club of Washington last month. "We haven't had to worry about this for 25 years, and while I wish it were otherwise, now we do."