The United States has proposed that NATO make unilateral cuts in its short-range nuclear weapons in an effort to bridge sharp divisions in the Western alliance over the missiles, a NATO official said Tuesday.

Under the proposal, the Soviet Union would be challenged to meet the lower levels of the 16-nation North Atlantic Treaty Organization, said the official, who spoke on condition of anonymity.The weapons would be trimmed as part of NATO plans to modernize the aging Lance surface-to-surface missile, a project that has sparked opposition in many European countries.

Further cuts in nuclear arms would be considered after progress was made in recently opened arms talks in Vienna on slashing conventional, or non-nuclear, forces in Europe, the official said.

In Washington, a U.S. official confirmed the account but said it was one of several options under consideration. The official, who spoke on condition of anonymity, said another option would be West Germany resuming research and development of a non-nuclear missile that could attack airfields and other targets now covered by the Lance.

West Germany, where the Lance launchers are based, last month demanded early talks with the Soviets on reducing short-range nuclear weapons. The United States and Britain have strongly opposed the idea.

The U.S. ideas, put forward last week to NATO representatives in Brussels, could serve as elements of a possible way to resolve the issue prior to a NATO summit May 29-30.

The NATO official described the American plan as "a proposal for a working document for how to proceed on the issue. It doesn't offer any compromise with the German proposal."

NATO officials have been trying to find satisfactory language on the weapons issue to include in a long-awaited blueprint of NATO's strategy in arms control.

A senior U.S. official suggested last month that NATO may fail to resolve the differences over the short-range weapons. He raised the possibility that the alliance would not reach a common position in time for the summit.

Such an outcome would likely lead to speculation about serious divisions in NATO. The Western nations are trying to present a united front in the face of defense cuts promised by Soviet President Mikhail S. Gorbachev.

The NATO official said the American plan draws together several ideas that have been put forward in the alliance.

It would take reductions proposed by U.S. Gen. John Galvin, NATO's supreme military commander in Europe, in a recent study of his nuclear weapons requirements and challenge the Soviets to meet the lower levels.

Galvin has pressed for NATO to agree to upgrade the Lance missile, arguing its modernization would permit a substantial reduction in nuclear artillery.

The Lance missile was introduced in 1972 and will become obsolete in 1995, military analysts say. It has a range of a little more than 60 miles. The new one would be extended to more than 250 miles, just under the limits of the Intermediate-range Nuclear Forces treaty.

Chancellor Helmut Kohl of West Germany said earlier in the year that a decision to deploy the new missiles should be delayed until 1991 or 1992, which would be after elections next year in Germany.

NATO defense ministers, at a nuclear strategy session last month, gave only lukewarm backing to the modernization program, saying nuclear forces "must be kept up-to-date where necessary."

U.S. Defense Secretary Dick Cheney said he was satisfied with the endorsement and was "reasonably confident" Congress would provide more money to continue development of the new generation Lance.

There are currently 88 Lance launchers, most of which are based in Germany. Officials have said the Warsaw Pact outnumbers NATO by about 12-to-1 in short-range nuclear missile launchers.

The alliance contends it needs to maintain its nuclear stockpile to balance the enormous superiority the East has built up in conventional arms.

NATO and the seven Warsaw Pact countries began talks in March on cutting conventional forces in Europe.