Using the site of history's first atomic bombing as a backdrop, Pope John Paul II today urged the world's superpowers to ban nuclear weapons and find a way to preserve peace.

In the major address of his four-day Japan tour, he appealed to heads of government to pledge that "war will never be tolerated or sought as a means of resolving differences.

"Let us promise our fellow human beings that we will work untiringly for disarmament and the banishing of all nuclear weapons."

He appeal was made in the Hiroshima Peace Memorial Park which encloses the spot where on Aug. 6, 1945, a U.S. plane dropped the first atomic bomb used in combat, destroying the city and killing more than 100,000 persons.

The pope underscored the international nature of his appeal by speaking from a text in nine different languages, beginning and ending in Japanese.

About 12,000 persons filled the small park that commemorates the bombing 35 years ago. The ceremony continued the string of rather small audiences the pope has attracted in this non-Christian country since he arrived Monday.

In the backround of the papal platform stood the skeletal of Hiroshima's old industrial promotion building that was all but destroyed in the bombing. It has been left intact, topped by the metal girders of its former dome, as a vivid reminder of the bomb's destructiveness.

After his speech, the pontiff toured the city's small museum of relics from the bombing. It includes shreds of tattered clothing worn by the victims, photographs of persons with blistered skin, and a scale model of the devastated city as it appeared on the day the bomb fell.

Estimates of the numbers killed and injured by the blast vary widely becuase it is not known exactly how many persons were in Hiroshima that day. A recent report, considered reliable, estimates that about 130,000 persons either were killed immediately or died of injuires within three months.

"On this very spot where, 35 years ago, the life of so many people was snuffed out in one fienery moment, I wish to appeal to the whole world on behalf of life, on behalf of humanity, or behalf of the future," the pope said.

"I bow my head as I recall the memory of thousands of men, women and children who lost thier lives in that one terrible moment, or who for long years carried in their bodies and minds those seeds of death which inexorably pursued their process of destruction," the pontiff said.

"The final balance of the human suffering that began here has not been fully drawn up, nor has the total human cost been tallied, especially when one sees what nuclear war has done -- and could still do -- to our ideas, or attitudes and our civilization."

In a later address here under the auspices of the United Nations University, the pope appealed for the humane uses of modern technology, a field in which Japan is among the leading countries. He said the Hiroshima experience had raised the moral crisis of whether technology would be used for good or evil.

The pope then went to Nagasaki, where he led mass at a major Catholic cathedral in the city where Catholicism first flourished in Japan.