OSLO (Reuters) - The Nobel Peace Prize winner’s campaign to ban nuclear weapons will not make the world more peaceful, the U.S. Embassy in Norway said, confirming its top diplomat will not attend next month’s award ceremony.

On Wednesday, the International Campaign to Abolish Nuclear Weapons (ICAN) accused the United States, Britain and France of snubbing its disarmament work by planning to send only second-rank diplomats in a coordinated move.

ICAN, a little-known organization that was a surprise choice for the prize, has been campaigning for the U.N. Treaty on the Prohibition of Nuclear Weapons, which was adopted by 122 nations in July this year.

But the treaty is not signed by - and would not apply to - any of the states that already have nuclear arms: the United States, Russia, China, Britain and France, as well as India, Pakistan and North Korea.

North Korea said it had successfully tested a new intercontinental ballistic missile on Wednesday in a “breakthrough” that puts the U.S. mainland within range of its nuclear weapons.

The U.S. Embassy in Oslo said it planned to send its acting deputy chief of mission instead of its acting ambassador to the Dec. 10 ceremony, attended by King Harald and Queen Sonja and the highlight of the diplomatic calendar in Norway.

“This year’s Nobel Peace Prize to ICAN for its efforts in support of the Treaty on the Prohibition of Nuclear Weapons, comes at a time of increased danger of nuclear proliferation,” the embassy said in the statement to Reuters on Thursday.

“This treaty will not make the world more peaceful, will not result in the elimination of a single nuclear weapon, and will not enhance any state’s security,” it said.

“This treaty ignores the current security challenges that make nuclear deterrence necessary, and risks undermining existing efforts to address global proliferation.”

Last month, U.S. President Donald Trump nominated Kenneth Braithwaite to the post of ambassador in Oslo, currently held by an acting ambassador.

While Britain and France will do the same as the United States in sending lower-ranking diplomats to the ceremony, the other two permanent members of the U.N. Security Council are taking different approaches.

The Russian embassy said it would send its ambassador to the ceremony. “The ambassador is planning to attend,” said Russian embassy spokeswoman Olga Kiriak.

The Chinese embassy said the ambassador was unavailable and that it had no plans to send someone else instead of him.

“We cannot be sure about the ambassador’s schedule at this time. He is on holiday,” said a press officer at the Chinese embassy, who did not give her name.