SEOUL: South Korean President Yoon Suk-yeol warned of an unprecedented joint response with allies if North Korea goes ahead with a nuclear test. Yoon called on China, North Korea's closest ally, to fulfil its responsibilities as a permanent member of the U.N. Security Council. He said not doing so would lead to an influx of military assets to the region.

China has the "responsibility" to engage in the denuclearisation process, Yoon said in his office. It is up to Beijing to decide whether it will exert that influence for peace and stability. North Korea's actions are leading to increased defence spending in countries around the region, including Japan, Yoon notes.

When asked what South Korea and its allies, the United States and Japan, would do if North Korea conducts a new nuclear test, Yoon said the response "will be something that has not been seen before", but declined to elaborate on what that would entail.

"It would be extremely unwise for North Korea to conduct a seventh nuclear test," he told Reuters.

Amid a record year for missile tests, North Korean leader Kim Jong Un said this week his country intends to have the world's most powerful nuclear force. South Korean and U.S. officials say Pyongyang may be preparing to resume testing nuclear weapons for the first time since 2017.

Yoon pressed Chinese President Xi Jinping to do more to rein in North Korea's nuclear and missile provocations. Xi urged Seoul to improve relations with Pyongyang. South Korea and the United States have agreed to deploy more U.S. "strategic assets" to the area. Yoon said he did not expect changes to the 28,500 American ground forces stationed in South Korea.

Yoon pressed Chinese President Xi Jinping to do more to rein in North Korea's nuclear and missile provocations. Xi urged Seoul to improve relations with Pyongyang. South Korea and the United States have agreed to deploy more U.S. "strategic assets" to the area. Yoon said he did not expect changes to the 28,500 American ground forces stationed in South Korea.

"We must respond consistently, and in lockstep with each other," Yoon says. China fought beside the North in the 1950-53 Korean War and has backed it economically and diplomatically since.

Boosting ties and coordination with Washington is the core of Yoon's foreign policy, he has said. Like his predecessor, Moon Jae-in, Yoon has treaded cautiously amid the rising U.S.-China rivalry. Any conflict between China and Taiwan should be resolved according to international norms and rules, he says.

"I am firmly opposed to any attempt to change the status quo unilaterally," Yoon said.

When asked about a role in a Taiwan conflict for South Korea or the U.S. troops stationed there, Yoon said that the country's forces would "consider the overall security situation" but that their most imminent concern would be North Korean military attempts to take advantage of the situation."What is important is responding to the imminent threat surrounding us and controlling the possible threat," he said.

South Korea, Japan and the U.S. have agreed to share information on North Korean missile tests.

Japan's military ambitions have long been a sensitive issue in neighbouring countries, many of which were invaded before or during World War II.
Yoon's predecessor stopped many of the trilateral exercises and nearly left an intelligence-sharing deal with Tokyo as relations soured.

Now Japan faces more and more threats from North Korea’s missile programme, including tests that overfly Japanese islands, Yoon said.

"I believe the Japanese government cannot be asleep at the wheel with the North Korean missile flights over their territory," he said.