Nato leaders at their anniversary summit in Washington have stressed their wish to keep Russia involved in the Kosovo crisis.

But it is unclear whether there is any room for constructive dialogue.

At the start of the Nato bombing of Yugoslavia, the relative positions of the alliance and Russia looked clear.

Moscow immediately condemned the Nato action and declared its support for the Serbs, a people with whom they have genuine ethnic, religious and cultural ties.

But even then, the Russians had a second agenda. They do not want to get involved in a war, even a cold war, with Nato over something which does not concern Russia's own sovereignty.

And their principal concern in their relations with the West right now is that they receive economic aid. Active opposition to Nato would not encourage this.

Mixed signals

Political, economic and cultural ties with Belgrade

As the bombing of Yugoslavia has continued relentlessly, Nato leaders have heard mixed signals coming out of Moscow.

The Russian President, Boris Yeltsin, has said that Nato could cause a third world war, only for his Foreign Minister, Igor Ivanov, to deny that this was actually the Russia's thinking.

One message which the alliance does seem to have taken from everything that Moscow has said is that the Russians most certainly do not want to become involved in a shooting war with Nato.

But now there could be a further complicating factor.

Oil embargo

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Alliance leaders are talking of introducing an oil embargo against Yugoslavia.

If this were to be rigorously enforced, ships suspected of taking oil to the country would be forcibly stopped and searched by Nato vessels.

As Russia is the single biggest importer of oil to Yugoslavia, such action would inevitably involve Moscow.

The Russian foreign minister said that Russia has no intention of ceasing supplying oil. But it seems likely that negotiations will continue behind the scenes on this issue.

Reassuring Russia

Nato is still going out of its way to reassure the Russians that, in the long run, they are perceived in Western capitals as being part of the solution to the Yugoslav crisis.

But they are also adamant that Nato policy will not be dictated by Moscow. Ironically, it could be President Milosevic who helps to push the two sides together.

After his meeting with Mr Chernomyrdin last week, he poured cold water on the Russian's upbeat assessment of their talks. His intransigence could lead to Moscow losing its patience with him.