Defense Secretary Frank Carlucci said on Monday that, despite encouraging changes within the Soviet Union, the Western NATO military alliance must remain ready to defend against Soviet military might.

"It would be ironic and dangerous if so-called Soviet `reforms' ended up affecting NATO forces more than the Warsaw pact's," Carlucci said in a speech to a conference sponsored by the Institute of Foreign Policy Analysis.It was co-sponsored by the Netherlands Atlantic Commission, the Eurogroup, the Western European Union and the North Atlantic Assembly.

A text of his speech was released in advance of delivery.

Carlucci said that while Soviet intentions could change quickly, the consequences of neglecting military readiness by countries in the North Atlantic Treaty Organization could take years to correct.

"It is important to realize that even where the Soviets appear to be disengaging - in Afghanistan, Angola and Cambodia - the catalyst has been persistent opposition, not a change in Kremlin ideology," Carlucci said.

The U.S. defense chief acknowledged some European NATO members have political and economic difficulties in raising their share of allied defense costs and get too little credit for what they already spend.

"On the other hand, America's NATO allies can and should contribute more to our common security," Carlucci said.

U.S. political critics, including Republicans and Democrats in Congress, have been pressing demands that some other members of the alliance must pay more of the cost of defending Western Europe.

The issue of defense sharing is to be a key agenda item when NATO defense ministers hold a two-day meeting in Brussels Dec. 1-2 that Carlucci is scheduled to attend.

The defense secretary said NATO allies are up against "a more sophisticated Soviet leadership under General Secretary (Mikhail) Gorbachev" and must separate facts from rhetoric.

"Kremlin leaders will continue to try and persuade us of their benign intentions and to exploit the trusting idealism of democratic peoples," he said.

Carlucci said if NATO allies stay strong and patient chances will be greatly improved for negotiating further significant arms reductions with the Soviet Union.