Maintaining a tough stance in the run-up to a U.S.-Russian summit, Russia's defense minister warned Washington on Tuesday that its withdrawal from the 1972 Anti-Ballistic Missile Treaty would shatter the entire system of arms control agreements.

``If we assume that the ABM Treaty loses force, it's logical to assume that the subsequent treaties that were based on it will also lose force,'' Sergei Ivanov told reporters after meeting with visiting Canadian Defense Minister Art Eggleton.

``That means we will enter a phase of total unpredictability in the sphere of global security,'' he added.

The ABM treaty prohibits a nationwide defense against ballistic missiles. The U.S. administration has tried unsuccessfully to persuade Moscow to amend the treaty to allow Washington to develop a limited missile defense system.

The missile defense issue will hang over the first meeting between Russian President Vladimir Putin and his U.S. counterpart George Bush, scheduled for June 16 in Ljubljana, Slovenia.

Ivanov said Moscow was ready to discuss the ABM issue, and praised the United States for launching a series of consultations rather than taking unilateral steps.

He added, however, that the consultations had been short on substance.

``It's too early to speak about any specific parameters yet,'' he said.

The United States has insisted that the planned defense system would be aimed at containing threats from potential nuclear nations, such as Iran and North Korea. Russia has acknowledged that there are some new threats but argued that they must be dealt with without modifying the ABM Treaty.

Ivanov said Russia and the United States would form working groups to continue discussions.