Russia would consider any further expansion of NATO forces near its borders a "demonstration of hostile intentions" and would take political and military measures to ensure its own security.
"We cannot see such a build-up of the alliance's military power near the border with Russia as anything else but a demonstration of hostile intentions," - Deputy Foreign Minister Vladimir Titov told Interfax.
The comments come days after U.S. President Barack Obama offered increased military support for eastern European NATO members to ease their concerns over Moscow.
Speaking last week in NATO-member Poland, Obama unveiled plans to spend up to $1 billion on supporting and training the armed forces of alliance states bordering Russia.
"We will be forced to undertake all necessary political and military measures to reliably safeguard our security" – Titov noted.