The proposals would see a total of 4,000 soldiers sent to Poland, Lithuania, Latvia and Estonia, according to military officials.
They are said to be keen to “send a message” to Moscow that NATO is committed to deterring possible Russian “aggression” in its eastern member states.
Last March, Moscow annexed the Ukrainian territory of Crimea – a move blasted by many leaders within the bloc, including David Cameron.
Russia is expected to consider NATO’s plan a violation of a 1994 agreement that bars “substantial” units from being deployed in frontier areas.
And countries such as Germany are reportedly concerned it could provoke a furious reaction from Moscow.
Steven Pfifer, a former US ambassador to Ukraine, said: “If you’re talking 800 to 1,000 troops [in each country], that would be big.
“And it would be designed to communicate to the Russians that NATO is serious – it will defend NATO territory.”
He added: “I wouldn’t put an armoured brigade in Eastern Estonia. I think that would be very provocative.
“But you could do other types of forces that would really not have the capability to head off and take St Petersburg.”
Earlier this month the Defence Secretary announced Britain would send 150 troops to Estonia, Latvia and Lithuania.
Michael Fallon said the deployment was “further reassurance for our allies… for NATO, for the Baltic states and for Poland”.
He added that the troops were part of a “more persistent presence by Nato forces” to respond to “any further Russian provocation and aggression”.
But Britain would have to agree to place its forces in Poland and the Baltic states under NATO command.
READ MORE: http://www.express.co.uk/news/world/615444/NATO-Vladimir-Putin-Russia-Poland-Lithuania-Latvia-Estonia-Crimea-Ukraine