The United States has announced the deployment of heavy weaponry including about 250 tanks across six former Soviet bloc nations.
US Defense Secretary Ashton Carter says the move will help reassure NATO allies facing threats from Russia and extremist groups.
"This pre-positioned European activity set includes tanks, infantry fighting vehicles and artillery. Estonia, as well as Lithuania, Latvia, Bulgaria, Romania and Poland have agreed to host company to battalion-sized elements of this equipment, which will be moved around the region for training and exercises."
Carter commented in Estonia where he met with his counterpart from that country, and those from Latvia and Lithuania.
The defense chiefs standing with Carter all spoke bluntly about the threat they perceive from Russia.
Estonian Defense Minister Sven Mikser says the additional military presence will be a deterrent.
"In global terms Russia is no match conventionally to US or to NATO, but here in this narrow corner of the world, Putin believes that he enjoys superiority, regional superiority and that makes us vulnerable in a sense. We are not talking about entering into a new Cold War type of arms race. We are not trying collectively to match Putin tank by tank or helicopter by helicopter in the Baltic Sea region either."
Responding earlier to the planned deployment, Russian President Vladimir Putin condemned the new NATO and US moves, accusing NATO of coming to the Russian borders.
Last week, Putin announced a drive to achieve 70 percent modern armament by 2020 for the country's armed forces.
