The Baltic States and Poland are set to receive four NATO battalion - around 4,000 troops - as Moscow increases its military activity in the region.

The news was confirmed by NATO officials on April 29, 2016.

According the Wall Street Journal, the United States is likely to provide two battalions. Meanwhile, the British and German armies will provide a further two.

During a visit to Brussels, U.S. Deputy Secretary of Defence, Robert Work, confirmed the size of the force and said the buildup was a response to Russia’s military activity within the Baltic region, where tensions have been rising.

"The Russians have been doing a lot of snap exercises right up against the borders with a lot of troops," Work said in an interview.

"From our perspective, we could argue this is extraordinarily provocative behaviour."

Russian officials have repeatedly said their own buildup and exercises are a response to NATO's troop buildup and aggressive posture to Moscow.

In February 2016, defence ministers approved the deployment of more troops to Eastern Europe.

NATO's military arm, the Supreme Headquarters Allied Powers Europe, has sent the recommendations to the alliance headquarters in Brussels, where they are being reviewed.

NATO officials want to make sure the force is multinational and are asking smaller allies to make contributions - such as logisticians - to support the troops.

According to NATO officials, the participation of a sizeable German force is particularly important.

They believe it will create a further effective deterrent against Russia and cement Berlin's emerging role as a key NATO player.

German officials said Friday they were considering plans ahead of a NATO summit in Warsaw in July to lead a Lithuania-based battalion. A final decision had not been reached.

Before the deployments are completed, one point of contention is whether the infantry forces within each battalion should be from one nation or multiple.

Some NATO officials believe each battalion should be from a single country, to ensure it can fight effectively.

Meanwhile, U.S. and other NATO officials they would like it to operate under the alliance flag and command and control system to act as a multinational deterrent to Russia.

Poland and the Baltic States have been long pressing for a larger NATO presence.

The U.S., Germany and the U.K. have said the force must be in keeping with the 1997 NATO-Russia Founding Act, which prohibits substantial numbers of combat troops from being permanently stationed on Russia's borders.

NATO officials said that while the 1997 document doesn't outline a specific number, a force of four battalions is in keeping with those restrictions.

U.S. and German officials say because the forces will rotate in and out of the Baltic region, they won't constitute a permanent force.

Andres Sang, a spokesman for the Estonian Defense Ministry, told the Postimees daily that it is still too early to say at this point how many extra soldiers will be stationed in the region and in which country.

"The decisions on potential placement of allied units here will be made probably at the NATO defence ministers meeting in June ahead of the NATO Warsaw summit,” he said.

“NATO member states have been weighing the need for some time to increase NATO presence in our region in connection with the complex security situation.

"Therefore news like this is most welcome.”