Russia is a traditional ally of the Serbs and favours a negotiated settlement of the Kosovo dispute. Both President Yeltsin and his prime minister, Yevgeny Primakov, have insisted that the Western powers must take Russia's views into account. Both clearly feel Russia was snubbed since Nato acted without the authorisation of the UN Security Council - where Russia is one of the five permanent members.
Russian leaders face conflicting pressures.
Some nationalists and communists have pressed the government to make a military response to Nato's action in the Balkans - an idea Mr Yeltsin has firmly rejected. Analysts are therefore watching what Russia does rather than what it says.