BRUSSELS — NATO military officials expressed concern Tuesday that nuclear arms agreements between the United States and the Soviet Union will leave Europe more vulnerable to an attack by conventional weapons of the Soviet Union and its Warsaw Pact allies.
U.S. military officials here are also worried that Soviet leader Mikhail S. Gorbachev will exploit that fear at next week's summit meeting with President Reagan by proposing immediate withdrawals of North Atlantic Treaty Organization and Warsaw Pact forces in Europe that would leave NATO, as one U.S. official put it, "worse off" than before the reductions.
While NATO defense ministers endorsed the treaty banning short- and medium-range nuclear weapons that is scheduled to be signed by U.S. and Soviet officials at the summit in Washington, uneasiness was voiced over the lack of progress in efforts to cut conventional weaponry in Europe.
The defense ministers of the 16 NATO nations are in Brussels this week for the semiannual Defense Planning Committee meetings. The focus of the talks has been the pending U.S.-Soviet treaty banning intermediate-range nuclear forces (INF), most of which are in Europe, and the effect that pact will have on NATO's ability to defend itself against a Warsaw Pact attack.
"There are hardly any promising prospects in the conventional field," said Gen. Wolfgang Altenburg, the West German officer who serves as chairman of NATO's military committee. "That is the main threat and the main problem."
U.S. military planners said that Gorbachev, seeking a "dramatic public opinion advantage," may propose next week that the Soviet Union withdraw as many as four military divisions from Europe and challenge Reagan to make a similar gesture. The offer would allow a smaller reduction on the U.S. side--perhaps only one or two divisions--as a signal of Gorbachev's recognition of the Warsaw Pact's marked superiority in manpower and firepower.
The Warsaw Pact has 230 divisions in place or rapidly transferable to the Central European front, while NATO has about 121 divisions, according to U.S. estimates.
Gorbachev can afford to make such an offer, said one U.S. military official requesting anonymity, because "he can give away a lot without sacrificing any defensive or offensive capability."
But it would present Reagan with a difficult choice: either risk alienating Europeans hungry for arms control by refusing the deal, or trade two battle-ready NATO divisions for four less well trained and less crucial Soviet units.
Gorbachev's 'Steel Teeth'
The deal also could present the danger that the public in the United States and Western Europe would be lulled into forgetting that "Mr. Gorbachev still has steel teeth," the U.S. military official said.
NATO officials also talked at length about improvements needed in the alliance's conventional capabilities. Weaknesses they identified included NATO's "sustainability" problem: The United States and its allies have ammunition stockpiled that would last fewer than 30 days under a full-scale Soviet attack. The Warsaw Pact is believed to have 90 days' supply on hand.
The Warsaw Pact outnumbers the West in tanks by a 2 to 1 margin, in artillery pieces by nearly 3 to 1 and in bombers by more than 5 to 1, according to Pentagon estimates.
NATO has problems distinguishing friendly from hostile aircraft and is at a comparative disadvantage in its ability to rapidly reinforce troops at the front, the officials said.
Defense Secretary Frank C. Carlucci, attending his first NATO session since replacing Caspar W. Weinberger late last month, said at a news conference Tuesday that while budget constraints may require a rethinking of U.S. military priorities, he remains committed to the defense of Europe.
"In looking at the budget cuts imposed at the Pentagon . . . nothing should be sacrosanct," Carlucci said. "But I strongly support the U.S. presence in Europe. In no sense am I advocating U.S. force cuts in Europe. Nor am I contemplating them."
The United States currently has 325,000 ground forces in Europe and 22,000 sailors on ships assigned to the European theater.