Russia has said it will adopt a beefed up military doctrine over NATO's plans to establish a rapid-response force in the wake of the rebellion in Ukraine's east, according a top Russian official.
The fact that the military infrastructure of the NATO member states is getting closer to our borders... will preserve its place as one of the external threats for the Russian Federation."
The Russian reaction came a day after the NATO chief said that the alliance would respond to the Ukraine crisis by creating a "spearhead" rapid reaction force, potentially including several thousand troops, that could be sent on operations in as little as two days.
"The fact that the military infrastructure of the NATO member states is getting closer to our borders, including via enlargement, will preserve its place as one of the external threats for the Russian Federation," Mikhail Popov, the deputy secretary of Russia's security council, told the RIA Novosti news agency.
He named US missile defence plans and the Ukraine crisis as other dangers to Russia's security.
“The USA wants to strengthen its troops in Baltic States. [They] have already decided to transfer its heavy weapons and military equipment, including tanks and armoured infantry vehicles, to Estonia. And all this next to Russia’s border,” said Popov.
“We consider that defining factor in [Moscow’s] relations with NATO will remain the unacceptability for Russia of the expansion plans of alliance’s military infrastructure to our borders, including via enlargement,” he added.
Moscow's announcement added a new and threatening new layer of tensions ahead of NATO's two-day summit that starts on Thursday in Wales and will see Ukraine's president Petro Poroshenko personally lobby his US counterpart Barack Obama for military help.
The 28-nation NATO already has a rapid reaction force but the new force is expected to be larger and be able to respond more quickly to a crisis.
The speed with which Russian forces infiltrated Ukraine's Crimea region in March has apparently pushed NATO to speed up its ability to respond if a similar crisis ever occurred on its territory.
"We will develop what I would call a spearhead ... a very high-readiness force able to deploy at very short notice. This spearhead would be provided by allies in rotation, and could include several thousand troops, ready to respond where needed with air, sea and special forces support," NATO secretary general Anders Fogh Rasmussen said on Monday.
Russia’s Popov said the mooted Western defence plan was "evidence of the desire of US and NATO leaders to continue their policy of aggravating tensions with Russia".
He added that Russia's 2010 military doctrine - a document that already permits the use of nuclear weapons should national security be considered in grave danger - would sharpen its focus on overcoming NATO and its new European missile defence system.
Defence minister Sergei Shoigu said in separate comments on Tuesday that Russia's armed forces would be given added muscle with the deployment of 230 new helicopters and jets by the end of the year.
The foreign minister, Sergei Lavrov, said that Ukrainian moves to seek NATO membership were aimed at undermining efforts to end the war in the east of the country.
Lavrov added that Washington should use its influence in Kiev to push for peace in eastern Ukraine.
"The most important thing is the need to talk sense into the party of war in Kiev, and in large part only the US can do this," Lavrov said.