PARIS, NOV. 19 -- Leaders of the 22 NATO and Warsaw Pact nations ended more than four decades of military confrontation today by signing a historic arms treaty that will dramatically reduce non-nuclear arsenals in Europe.

In a companion pledge disavowing any future aggression against each other, the two rival blocs declared that the end of the Cold War era means that "they are no longer adversaries, will build new partnerships and extend to each other the hand of friendship."

After burying their conflict in a lavish signing ceremony at the French presidential palace, the leaders of the 16 North Atlantic Treaty Organization members and six Warsaw Pact nations joined the heads of 12 neutral nations to open three days of speeches and deliberations about the future course of an undivided Europe.

The 34 participants in the Conference on Security and Cooperation in Europe (CSCE), which comprises the United States, Canada and all European countries except Albania, are expected to endorse free elections and free markets for their societies. They will also agree to hold annual gatherings for foreign ministers and summit conferences every two years to sustain peace across the continent.

"It is the first time in history that we witness a change in the depth of the European landscape which is not the outcome of a war or bloody revolution," French President Francois Mitterrand declared in opening the CSCE summit. "We do not have sitting here either victors or vanquished, but free countries equal in dignity.

"For more than 40 years, we have known stability without freedom. Henceforth, we want freedom in stability," Mitterrand said.

President Bush and Soviet President Mikhail Gorbachev gave short speeches praising the new world order that has emerged with the collapse of Eastern Europe's totalitarian regimes and the flowering of new democracies.

"Our country has changed and will never be the same as it was before," Gorbachev said. "We have opened up to the world and the world has opened up in response."

While the conference's focus is on the future of Europe, much attention is being paid in bilateral exchanges here to the Persian Gulf crisis.

Bush today discussed Iraq's continuing occupation of Kuwait with British Prime Minister Margaret Thatcher over breakfast and with Gorbachev over dinner. The gulf issue is expected to be raised at a closed session of all leaders on Tuesday.

The Conventional Armed Forces in Europe treaty reducing non-nuclear weapons on the continent was hailed as making any surprise attack impossible through a complex monitoring and verification schedule that will oversee the destruction of vast amounts of equipment within 40 months.

Under the treaty, neither NATO nor the moribund Warsaw Pact may maintain more than 20,000 tanks, 20,000 artillery pieces, 30,000 armored combat vehicles, 6,800 combat aircraft and 2,000 attack helicopters between the Atlantic Ocean and the Ural Mountains.

New limits on each nation's troops levels will be established in negotiations scheduled to begin in January.

The Warsaw Pact's overwhelming superiority in conventional weapons means NATO countries will only make about one-tenth of the weapons reductions to meet the new limits established by the treaty. Because the treaty restricts the proportion of arms that can be held by any one country to about one-third the total permitted for all countries, the Soviets will have to remove as many as 19,000 tanks from Europe.

But U.S. officials said some "surprises" have arisen over the number of artillery pieces the Soviets are supposed to remove. When data on cuts required by the treaty was exchanged in Vienna on Sunday, the Soviets gave a number "much lower than anticipated," a senior American official said.

The Soviets said they only need to reduce their artillery by 500, but non-government arms experts say the number was expected to be as high as 5,000.

The Soviets also identified less than half as many military sites to be inspected under the treaty than the United States had expected.

James Woolsey, the U.S. negotiator for the conventional-forces treaty, said the Soviet figures were "still being analyzed" and that the treaty data could be adjusted during the next 90 days.

Woolsey said, however, that the issue was "important" and "serious."

Western officials said the Soviets' low arms-reduction numbers may merely reflect the extent to which Moscow already has pulled weapons out of Europe.

In recent months, the Soviets have moved massive amounts of tanks and other military equipment across the Ural Mountains to exclude them from the treaty restrictions. U.S. officials have complained that while the practice was not illegal, it was contrary to the spirit of the treaty.