Russian President Boris Yeltsin stepped up his personal telephone diplomacy with NATO leaders on Tuesday but told his top negotiator to take a tough line in talks with the Western defense alliance.

The Kremlin said Yeltsin discussed security matters with West German Chancellor Helmut Kohl and new British Prime Minister Tony Blair, continuing what the Kremlin says will be several days of telephone diplomacy with NATO leaders.Itar-Tass news agency said Yeltsin had earlier instructed Foreign Minister Yevgeny Primakov to take a firm line in defending Russia's interests at Tuesday's meeting in Moscow with NATO Secretary General Javier Solana.

"The president confirmed the foreign minister's mandate for the talks and noted the need to continue the firm Russian line, based on defending the country's interests especially on military questions," Tass said.

Solana was due to arrive in Moscow on Tuesday evening for the talks which Primakov says will decide whether Russia and NATO can sign an agreement on a peaceful new relationship after years of mistrust.

Some Kremlin sources say Russia has already decided to sign the deal in Paris on May 27 but will keep up the uncertainty and anti-NATO rhetoric until the last minute to appease domestic opponents who fear Yeltsin is selling out national interests.

Primakov said Russia still hoped Tuesday's talks with Solana would be the last before May 27.

"We would like it to be so, but not everything depends on us. Let us wait and see what Mr. Solana brings," he told a joint news conference with visiting Swiss Foreign Minister Flavio Cotti.

The Russia-NATO deal is intended to overcome Moscow's strong objections to the North Atlantic Treaty Organisation's plans to expand to take in new members from the former Soviet bloc.