NEWS ANALYSIS : Claes Off to a Rocky Start as NATO Chief : Europe: Possible links to Belgian scandal may weaken his power just as the alliance needs strong leadership.

BRUSSELS —  Because NATO Secretary General Willy Claes is a committed Socialist whose previous, best-known involvement in military affairs was his active, 1980s opposition to U.S. medium-range nuclear missile deployments, no one expected him to slip into his new role without a few problems.

Still, few foresaw such a rocky start for a man who also came to the job with a reputation as a competent, honest and successful politician.

There have already been calls for Claes to resign his post with the North Atlantic Treaty Organization, and his difficulties are certain to weaken his power if he stays--at a time when the alliance desperately needs strong leadership.

The latest setback for the 55-year-old former Belgian foreign minister stems not from his position as head of the 16-nation NATO but from the suspicion that he may be linked to one of the biggest domestic political scandals in recent Belgian history.

For months, Claes strenuously denied any knowledge of the $2 million in “gifts” paid to his Socialist Party-Flemish by the Italian helicopter producer Agusta in 1989, shortly after the company won a lucrative contract to supply the Belgian army.

But last month, after Foreign Minister Frank Vandenbroucke, a senior Socialist Party colleague, asserted that Claes was present at a meeting in which the prospect of “gifts” for the party was discussed, the new NATO chief was forced to admit that he may have known something about the matter after all.

“It was only mentioned and did not last more than 10 seconds,” he told Belgian national radio.

Claes was economics minister at the time and helped negotiate the Agusta contract.

Although Claes is widely seen in Belgium as an honest public figure and still maintains that he did nothing wrong, his admission stunned supporters, as did the subsequent arrest last week on corruption charges of the man who in 1989 ran his ministerial office.

The scandal grew Wednesday with the apparent suicide of Jacques Lefebvre, a retired Belgian air force general who was the chief of staff of his branch of the military when the Agusta deal was signed. His body and two suicide notes were found in a Brussels hotel room a day after he was publicly implicated in the affair.

Mounting doubts about Claes’ role in the scandal brought statements of concern from senior political figures in Germany and the Netherlands, while in Denmark, some political parties suggested that it was time for Claes to relinquish his NATO post to former Danish Foreign Minister Uffe Ellemann-Jensen.

So far, Claes has won strong support from the Clinton Administration, which applauded his appointment last September, while British and Spanish leaders have issued statements backing him.

At a meeting in Washington on Tuesday, Claes and President Clinton talked about the expansion of NATO into Eastern Europe, and about Russia and Bosnia-Herzegovina.

They did not take up Claes’ own situation. Mike McCurry, the White House press secretary, said that because of Vice President Al Gore’s public endorsement of Claes last year, “I don’t believe there would be a need for that.”

Since stepping into the NATO job after the death of his predecessor, Manfred Woerner, Claes has faced a series of mini-crises.

Under his chairmanship, sharp transatlantic differences over how to deal with the war in Bosnia eased, at least for a while, as alliance defense ministers agreed in December on statements supporting the U.N. peacekeepers there and then worked together on a plan to rescue them if they had to withdraw.

But Claes also fell into a trap set by Russian Foreign Minister Andrei V. Kozyrev, who cleverly used access to the world’s press at NATO headquarters to complain about plans to expand the alliance eastward.

Claes’ problems are almost certain to affect his ability to lead the alliance as it searches for a new identity and a new role in the post-Cold War world. With little real statutory power, NATO secretaries general have historically had to rely on their moral authority and powers of persuasion to give the alliance strong direction and unity.

Times staff writer Paul Richter in Washington and Isabelle Maelcamp of The Times’ Brussels Bureau contributed to this report.