World Leaders Call for Peaceful New Year : War threat: They recognize the achievements of the past year but fear a conflict in the Mideast.

World leaders, mindful of the threat of war, Tuesday sounded a call for peace in the new year while people in the streets welcomed 1991 with the customary toasts and celebrations.

Soviet President Mikhail S. Gorbachev, addressing the American people, welcomed a superpower summit planned for February to conclude a treaty reducing strategic weapons, and summed up 1990 as a momentous year: “The Cold War is over. There is no more danger of nuclear catastrophe. The horizons of peace have been widened.”

But he said Iraqi President Saddam Hussein’s “aggression” threatens to destroy the peace that arrived with East-West harmony. The international community “should find strength to overcome this obstacle,” he said.

President Bush, in his reciprocal address to the Soviet people, saluted Gorbachev for undertaking an “arduous journey” to a new society.

Pope John Paul II, acknowledging the threat of war in the Persian Gulf, offered a special New Year’s wish that 1991 will be a year of peace in the Middle East.

“Oh New Year, . . . may you be the year of salvation. May you be the year of peace,” said the pontiff, speaking to the faithful in St. Peter’s Square.

As usual, celebration was loud and raucous from the firecracker-popping streets of Manila, where pyrotechnics took its annual toll in life and limb, to London’s Trafalgar Square, where 60,000 people partied.

Paris marked the stroke of midnight noisily, with whistles, honking horns and the pops of thousands of champagne corks. Tourists filled the Moulin Rouge and other dance halls.

In New York’s Times Square, the steel ball that traditionally drops at midnight was lit for the first time with red, white and blue bulbs in a gesture to the soldiers overseas.

For those troops, New Year’s was generally low-key. On the minds of many was how they might perform in an attack to drive Iraq from Kuwait, a military action that the United Nations has authorized if Iraq does not withdraw by Jan. 15.

Germans began their first year in decades as a single nation, and fireworks lit the sky over the Brandenburg Gate, which not long ago stood above the wall that divided East from West.

Chancellor Helmut Kohl in a New Year’s Eve speech called for support for Soviet reforms to maintain peace on the continent: “No one has a bigger interest in that than we Germans in the heart of Europe.”

In a land where Cold War division remains, leaders of North and South Korea told their people that reunification of the divided peninsula is not just a dream but a goal that must be achieved soon.

President Roh Tae Woo told South Koreans to prepare for unification with North Korea, saying the ice between the two countries, divided in 1945, would begin to thaw in 1991.

Roh repeated his call for a unified Korean nation by the end of the century.

In Pyongyang, North Korean President Kim Il Sung also spoke of the need for urgent action. A short television clip of Kim speaking appeared on the evening news in Seoul, a rare sight in South Korea.

“We must not allow the division of our country to drag on beyond half a century but accomplish the historic cause of national reunification within the next several years,” Kim told an audience of government leaders and academics.