It looks like there was mistrust developing before the NATO-Russia Council, with the bombings of Yugoslavia.
In 1999, Russia condemned the NATO bombing of Yugoslavia, which was done without a prior authorization by the United Nations Security Council, required by the international law. For many in Moscow, a combination of NATO’s incorporation of Eastern Europe and its military attack on sovereign Yugoslavia exposed American promises of Russia’s inclusion into a new European security architecture as a deceit. Yeltsin’s critics said: ‘Belgrade today, Moscow tomorrow!’