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On Thursday, Mr Cook met his Russian counterpart, Igor Ivanov, and announced he would be visiting Moscow in the near future to continue the diplomatic initiative.

The Prime Minister, Tony Blair, who also met Mr Ivanov, could visit Russia next year after an invitation by President Boris Yeltsin's government.

'Relationship for the millennium'

In an article published in the Russian newspaper Nezavisimaya Gazeta, Mr Cook said the Kosovo crisis had been the tensest period in the UK's relations with Russia since the end of the Cold War.

Mr Blair may also visit Russia next year

But he went on to say Moscow remained a vitally important partner and he hoped they could now seek a common approach in dealing with Kosovo.

Mr Cook said: "This visit does mark a step change in our relations. We want a new and stronger relationship for the new millennium."

The foreign secretary said the UK would take a positive and constructive approach at an International Monetary Fund (IMF) meeting next week to consider further lending to Russia.

He continued: "This visit has given us in Britain the opportunity to extend the hand of friendship to Russia and to provide a signal of our full engagement with Russia in tackling global issues."

Postponed visit

Mr Ivanov is on a visit that was to have taken place in May, but was cancelled by President Yeltsin in protest at Nato's bombing of the Chinese embassy in Belgrade.

Mr Cook has responded to Russian complaints that Moscow was ignored during the Kosovo conflict by agreeing to consult by telephone before future international meetings, to try to align views.

He said the two ministers had agreed to consult ahead of next week's Sarajevo summit on Kosovo reconstruction.

But Mr Ivanov made it clear that differences remained over Kosovo, saying Russia believed Yugoslavia should be given reconstruction aid.

The UK opposes such a move while Yugoslav President Slobodan Milosevic is still in power.

Mr Ivanov's meeting with Mr Blair and Mr Cook was preceded by a visit to the Imperial War Museum, where he laid a wreath at the memorial for Russians killed in World War II.

The archive contains details about the death of Tsar Nicholas II

Afterwards, Mr Ivanov responded positively to questions concerning relations with the UK.

He said: "I think there are very good possibilities for relations between Britain and Russia and I think that in particular there are good relations between both in the military sphere."

But the Kremlin still seems to view Nato as a threat. Last month, the Russians' biggest military exercises since the Cold War caused alarm in the West, when they test-fired strategic missiles.

Archives swapped

The two foreign ministers also signed an agreement on archival co-operation.

Mr Ivanov handed over papers from Moscow archives belonging to UK servicemen captured by the Germans during World War II.

The documents were taken to Moscow with other material seized by the Red Army and the Soviet secret police after the defeat of Nazi Germany in 1945.

In turn, Mr Cook presented Mr Ivanov with papers from the UK's files dealing with the death of Tsar Nicholas II.

The documents, most of which are familiar to historians and have been published, include a telegram sent from Moscow on July 17 by the British consul Robert Bruce Lockhart.

The telegram is the first report of the tsar's murder the previous day in Yekaterinburg.

Mr Lockhart believed that he was the first person to convey the news to the outside world but the coded telegram failed to arrive at the Foreign Office in London until 28 July, by which time the death of the tsar had been already announced.