NATO expressed disappointment on Saturday at Russia's decision to suspend participation in the Conventional Forces in Europe (CFE) Treaty.
"It's a disappointing move, a step backwards," NATO spokesman James Appathurai told Brussels-based media on Saturday.
"NATO considers this treaty to be an important foundation of European security and stability."
Russian President Vladimir Putin has signed a decree suspending Russia's participation in the CFE treaty due to "extraordinary circumstances which affect the security of the Russian Federation and require immediate measures," said the Kremlin press service on Saturday.
During the CFE treaty suspension, Russia will not be bound by any conventional weapons limits. Information provision and inspections will be suspended, the Russia Foreign Ministry said in a statement following the Kremlin announcement.
Real Russian weaponry numbers will depend on military and political needs, including readiness of other treaty member countries to show adequate restraint, the Foreign Ministry statement said.
The CFE treaty aims to maintain military balance in Europe by setting limits on key categories of conventional military equipment for NATO countries and those of the rival Warsaw Pact.
It was signed in 1990 and an adapted treaty was agreed upon in 1999. So far only Russia, Belarus, Kazakhstan and Ukraine have ratified the 1999 treaty. NATO countries have refused to do so, insisting that Russia must first fulfill the so-called "Istanbul obligations " -- withdrawal of Russian troops from Moldova and Georgia.