Nagasaki, Japan ? A siren wailed and a bronze bell rang out Tuesday as Nagasaki marked the moment 60 years ago when an American plane dropped a plutonium bomb, killing tens of thousands and sealing Japan’s defeat in World War II.

About 6,000 people, including hundreds of aging bomb survivors, crowded into Nagasaki’s Peace Memorial Park, just a few hundred yards from the center of the blast, for a solemn remembrance and moment of silence.

When the silence ended, Nagasaki Mayor Iccho Itoh had some angry words for the leaders of the nuclear powers, and especially the United States.

“To the citizens of the United States of America: We understand your anger and anxiety over the memories of the horror of the 9-11 terrorist attacks,” he said. “Yet, is your security enhanced by your government’s policies of maintaining 10,000 nuclear weapons.”

Itoh also urged Japan to get out from under the U.S. “nuclear umbrella.” About 50,000 U.S. troops are deployed throughout Japan under a post World War II mutual security pact.

Tuesday’s remembrances began just after sunrise, as hundreds of Catholics joined in a special Mass at Urakami Cathedral, which at the time of the bombing was the largest in Asia with 12,000 parishioners – 8,500 of whom are believed to have been killed.

People burn incense in front of the Statue of Peace at Nagasaki's Peace Park, in Nagasaki, southwestern Japan today to mark the 60th anniversary of atomic bombing.

When the cloudy sky lit up in a sudden flash at 11:02 a.m. in 1945, two priests were hearing confessions inside the cathedral and 30 faithful were inside. Everyone in the church died and the statues around them turned black because of the intense heat.

Nagasaki’s devastation has been overshadowed by Hiroshima, where some 55,000 people swarmed into that city’s Peace Memorial Park to mark the 60th anniversary of the attack last week.

The people here, however, have not forgotten.

“Together with some 260,000 A-bomb survivors … I swear in the presence of the souls of the victims of the atomic bombing to continue to tirelessly demand that Nagasaki be the last A-bomb site,” said Fumie Sakamoto, who represented the survivors at Tuesday’s memorial. Sakamoto was a junior high student when Nagasaki was bombed.

The remains of thousands of the dead have never been found. Japanese estimates of the death toll itself range from 60,000 to 80,000. Nagasaki officials today used 74,000 as the death figure.