The United States has the responsibility to ensure that nuclear weapons are never used again, Secretary of State Antony Blinken said Monday as Japan's Nagasaki city marked the 76th anniversary of the U.S. atomic bombing in World War II.

"On the solemn anniversary of the atomic bombing of Nagasaki, we remember the horrific power of nuclear weapons -- the enormity of the death and destruction they can deliver -- and reaffirm the responsibility of the U.S. and all nations to ensure such weapons are never used again," he tweeted.

Blinken's remarks come as nuclear superpowers remain under scrutiny with a U.N. treaty to ban atomic weapons coming into effect in January with the support of many non-nuclear states.

U.S. President Joe Biden said during last year's election campaign that he will "work to bring us closer to a world without nuclear weapons, so that the horrors of Hiroshima and Nagasaki are never repeated."

The United States dropped atomic bombs on the two Japanese cities in 1945, making them the world's first and second locations to come under nuclear attack in war.

But Biden also said during the campaign that creating "a world free from the threat of nuclear weapons" is an "ultimate" goal.

Biden served as vice president under Barack Obama, the winner of the 2009 Nobel Peace Prize who, however, failed to achieve his vision of a world without nuclear weapons.

The Biden administration, launched in January, has agreed with Russia to extend their nuclear arms reduction treaty and has launched a bilateral Strategic Stability Dialogue toward future arms control initiatives.

In July, on the eve of the 76th anniversary of the world's first nuclear test conducted in the U.S. western state of New Mexico, Biden said Hiroshima and Nagasaki "opened our eyes to the truth that a nuclear war must never be fought."

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