The move follows months of verbal sparring with Europe and Washington on a range of fronts, including US plans for a missile shield in eastern Europe, proposed independence for Serbia's Kosovo province and Moscow's energy policies.

The Kremlin said President Vladimir Putin had signed a decree suspending Russia's role in the Conventional Forces in Europe (CFE) treaty for reasons of "national security."

NATO, Washington and the European Union expressed regret and disappointment at the Russian move.

The pact was adopted in 1990 to limit the number of tanks, heavy artillery and combat aircraft deployed and stored between the Atlantic and Russia's Ural mountains.

Russia criticizes the West for failing to ratify a version amended to take into account the new post-Cold War situation. Talks last month with NATO states ended without progress.

The pact requires signatories to notify other member states 150 days before suspending participation. The Foreign Ministry said it would start the notification process on Saturday.

If no solution was found in the five-month period, Russia would stop providing information and stop allowing inspections of its heavy weapons.