NATO is set to deploy four battalions to Poland and the Baltic States as part of its response to Russia's actions in Ukraine, the chief of the Western military alliance said Monday.
The move is likely to ratchet up tensions with Moscow, which has repeatedly warned that an eastward NATO expansion threatens its national security.
"NATO has taken robust action to protect our nations and to contribute to stability in our neighbourhood. But the challenges we face are enduring. So we need to be prepared for the long haul," NATO Secretary General Jens Stoltenberg said in Brussels, one day before the alliance's defence ministers are due to discuss the deployment.
"Based on the advice of our military planners, we will agree to deploy by rotation four robust multinational battalions in the Baltic states and in Poland," Stoltenberg added. "This will send a clear signal that NATO stands ready to defend any ally."
The military alliance's eastern-most members have said that they feel threatened by Russia, which has been accused of violating international law by annexing the Ukrainian peninsula of Crimea. Its support for separatists in eastern Ukraine has also raised concerns.
The new NATO troop deployment is expected to involve 3,000 to 4,000 soldiers. The United States, Britain and Germany are said to be in line to lead three of the battalions, while the fourth lead nation is still to be confirmed.
Stoltenberg said the deployment to Estonia, Latvia, Lithuania and Poland will be open-ended, with no end date decided upon yet.