The world is holding its breath over the possibility North Korea might carry out a nuclear bomb test, the head of the United Nations’ nuclear watchdog, the International Atomic Energy Agency (IAEA), has said.

Officials in the United States and South Korea have warned for months that Pyongyang is preparing for a nuclear test after a five-year suspension — a move that would signal North Korea speeding ahead with the development of advanced weapons capabilities.

“Everybody is holding its breath about this, because another nuclear test would be yet another confirmation of a program which is moving full steam ahead, in a way that is incredibly, incredibly concerning,” IAEA Director General Rafael Grossi said on Thursday.

“Further tests, of course, means that they are refining the preparations and the construction of their arsenal,” Grossi told reporters.

“So we are following this very, very closely. We hope it doesn’t happen, but indications unfortunately go in another direction,” he said.

Fears of a North Korean nuclear bomb test — which would be their first detonation of a device since 2017 — follow Pyongyang’s recently demonstrated range of short- and long-range ballistic missile capabilities, which have left neighbours South Korea and Japan deeply concerned about North Korea’s intentions.

On Wednesday, the US, South Korea and Japan said an “unparalleled” scale of response would be warranted if North Korea conducts a seventh test of a nuclear weapon.

South Korean First Vice Foreign Minister Cho Hyun-dong told a news conference in Tokyo the three allies had “agreed that an unparalleled scale of response would be necessary if North Korea pushes ahead with a seventh nuclear test”.

Cho made his comments alongside Japanese Vice Foreign Minister Takeo Mori and US Deputy Secretary of State Wendy Sherman.

The IAEA’s Grossi said he did not think a North Korea test was immediately imminent.

“We see preparation, we see lots of things, but in terms of degrees of imminency, no,” he said in response to a question.

In a new assessment of US defence needs and priorities released on Thursday, the Pentagon said a nuclear attack by North Korea on Washington’s interests or allies would lead to the “end” of North Korean leader Kim Jong Un’s regime.

“Our strategy for North Korea recognizes the threat posed by its nuclear, chemical, missile, and conventional capabilities, and in particular the need to make clear to the Kim regime the dire consequences should it use nuclear weapons,” the US’s Nuclear Posture Review 2022 states.

“Any nuclear attack by North Korea against the United States or its Allies and partners is unacceptable and will result in the end of that regime.”

“There is no scenario in which the Kim regime could employ nuclear weapons and survive,” the document says.

“Further, we will hold the regime responsible for any transfers it makes of nuclear weapons technology, material, or expertise to any state or non-state actor.”

North Korea has said its missile launches are in response to the threat posed by the US and its South Korean allies. Angered by South Korea’s military exercises with the US in recent months — including joint military drills that involved the USS Ronald Reagan aircraft carrier and accompanying ships — Pyongyang last week fired hundreds of artillery shells off its coast in what it called a warning to its southern neighbour.

PHOTO CAPTION:•A submarine-launched ballistic missile displayed in Kim Il Sung Square during a military parade in Pyongyang, North Korea, in 2017 [File: Wong Maye-E/AP]

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