BRUSSELS–In a move sure to anger Russia, NATO announced on Wednesday firm plans to deploy a significant number of troops into Eastern Europe.

After a day of meeting with alliance members, NATO Secretary General Jens Stoltenberg made the announcement during a press conference. Though he was vague on details, he added that final decisions regarding the make-up of the multi-national force will be ironed out in June, and voted upon at the next NATO meeting in July.

“We will have as much presence in the east as needed,” Stoltenberg said, adding that the forces will be non-permanent and constantly rotating.

NATO’s new so-called “deterrent” posture was touted by Secretary of Defense Ashton B. Carter Tuesday on the heels of his announcement that the Pentagon would be pumping $3.4 billion into forces and training stationed in Europe.

The U.S. forces are separate from those announced by NATO, but will provide a significant boost to allied forces distributed throughout Europe. According to a U.S. senior defense official, speaking on the condition of anonymity to discuss issues currently in the planning phases, the brigade-sized force of approximately 3,000 troops will be distributed throughout the Baltic states, as well as Bulgaria, and Germany.

“This is the first chapter of a very good book for Europe in terms of U.S. commitment,” the official said, adding that in lieu of the United States’ commitment, Carter has not asked his European allies to match the U.S. pledge. Instead, according to the official, the U.S. expects those on the continent to commit troops simply because the United States is not in a geographic position to quickly respond to any future aggression.

Stoltenberg noted that the United States commitment to Europe and subsequently NATO has played a big part in the alliance’s reinvigorated position, but made sure to highlight the contribution of other countries that continue to pledge forces to the alliance.

Earlier this week, Britain announced the deployment of five warships spread throughout the North Atlantic, the North Sea, the Baltics and the Mediterranean.

“We have tripled the size of the NATO Response Force to more than 40,000 troops, with the new Spearhead Force at its core,” Stoltenberg said. “And we have activated six small headquarters in our eastern Allies, and are setting up two more.”

The move by NATO has since been called “destabilizing” by the Russian Foreign Ministry and is designed to contain Russia, according to a Reuters report.

The “Spearhead Force” is the Very High Readiness Joint Task Force, or VJTF, which was stood up in July of last year. The VJTF was built specifically to counter fast-moving threats across the alliance, it still requires a potentially lengthy NATO voting process to be deployed.

In addition to the VJTF, Stoltenberg highlighted the increased NATO presence in the eastern part of the alliance, namely Turkey. In recent months NATO has increased air patrols, aerial surveillance, and the deployment of anti-missile defenses.

What was not mentioned by Stoltenberg, according to the senior U.S. defense official, was an ongoing dialogue between Turkey and Germany to help assist with the current influx of refugees fleeing into Europe from the Syrian civil war. According to the official, this could involve a joint maritime mission between the two countries.