COPENHAGEN, JUNE 5 -- Soviet Foreign Minister Eduard Shevardnadze said today his government will withdraw 1,500 nuclear warheads and some associated short-range weaponry from Central Europe, but U.S. officials cautioned that it was not clear whether he was counting weapons whose withdrawal Moscow had announced earlier.

Addressing a meeting here of foreign ministers from the 35-nation Conference on Security and Cooperation in Europe (CSCE), Shevardnadze caused a stir when he announced that the Soviets plan to withdraw 60 tactical missile launchers, more than 250 atomic artillery units and 1,500 nuclear warheads from Central Europe to spur negotiations with the United States on reducing short-range nuclear weapons.

"These are new figures, and they seem to be quite impressive figures," Shevardnadze told reporters tonight following a two-hour meeting with Secretary of State James A. Baker III. But he declined to give specifics about where and how the cuts would be made or what percentage of the Soviet nuclear arsenal would be withdrawn from Central Europe.

Baker, standing at Shevardnadze's side, said diplomatically that the United States and NATO welcomed the news "because the Soviet Union has a significant advantage in these types of weapons." Beyond that, Baker said only that "we are still taking a look at and analyzing" the Soviet move.

Earlier, Baker and other U.S. officials said they did not know whether the figures cited by Shevardnadze represented all new cuts or were made up at least in part by other unilateral withdrawals of short-range nuclear arms the Soviets had announced earlier. In particular, the officials said, there are questions about how many of the Soviet weapons to be removed might be those of the 500,000 Soviet troops whom President Mikhail Gorbachev promised to withdraw from Central Europe in December 1988.

"We really don't know the degree to which {Shevardnadze} is talking about an accumulation of withdrawals -- that is combining perhaps additional withdrawals with some unilateral withdrawals that they had announced earlier," Baker said. The Kremlin promised to withdraw 500 nuclear artillery shells from the region after Baker met Shevardnadze in Moscow last year.

"So we really don't know yet whether or not it simply means withdrawal or withdrawal and destruction, whether or not these are weapons that would have been withdrawn in any event as a consequence of the unilateral withdrawal of troops," he added.

Another senior U.S. official, who asked not to be identified, was even more skeptical. "This could be an elaborate public relations ploy," he said. Moscow already have promised Hungary and Czechoslovakia that it would remove its forces from those countries, he noted, "So are they promising to do in one forum what they already promised to do in another?"

Vitaly Churkin, an adviser to Shevardnadze, said he had been assured that the figures were "authoritative" but added that he "could give no specificity about the Soviet proposal" or say how much of the total Soviet short-range nuclear weaponry it represented.

In his speech, Shevardnadze said the Soviet move was a gesture to help launch the short-range arms reduction talks that the Soviets want to begin this fall. President Bush recently won the backing of the Western alliance for his position that the talks should begin after the signing of a treaty reducing European conventional forces. The administration earlier had said such talks should await the treaty's implementation.

Shevardnadze said the Soviet plan for a unilateral cutback had been introduced at "the working level" during last week's summit in Washington between Gorbachev and President Bush. But U.S. officials said they had no recollection of the idea coming up in Washington.

The CSCE meeting, which involves 33 European states plus the United States and Canada, is supposed to deal with human rights. However, in addition to the arms control element introduced by Shevardnadze, he and Baker used their get-together to discuss ways of ending the impasse over unification of Germany.

At the summit, Gorbachev forcefully reiterated Soviet opposition to a united Germany being a member of NATO. But, while en route here, Baker told reporters he wanted to explore statements by Shevardnadze that the German problem might be resolved in some kind of agreement between NATO and the Soviet-led Warsaw Pact.

Baker said the U.S. side had been unable to get Shevardnadze "to flesh out what he meant." But the Soviet minister referred to it again in vague terms during his speech today.

After their meeting tonight, Baker said he had "a little bit better idea" of the Soviets' thinking, but he refused to elaborate. Shevardnadze added, "That is not for public discussion, as we need to do some more homework."

But Shevardnadze also alluded to the need for the two alliances to shift from their original military functions to a more political role, and he hinted that such a move might play a part in working out a compromise over Germany's future alliances.