"Discussing the denuclearization of the Korean peninsula today is a grave political provocation," a North Korean foreign ministry spokesperson said, quoted by the official KCNA news agency, adding that the issue infringes on the North's constitution.

"It would infringe upon the constitutional position of our country [North Korea] as a nuclear weapons state," the spokesperson said.

Seoul, Tokyo and Beijing reaffirmed their commitment to the "denuclearization of the Korean peninsula" and peace on Wednesday at their first trilateral summit in nearly five years, also pledging to strengthen economic cooperation and push for a three-way free trade agreement.

The issue was not officially on the agenda of the talks between South Korean President Yoon Suk-yeol, Chinese Premier Li Keqiang and Japanese Prime Minister Fumio Kishida.

"We reconfirm our positions on peace and stability in the region and the denuclearization of the Korean peninsula," the leaders said in a joint statement, adding that they would "continue positive efforts towards a political resolution" of the issue.

The topic was thrust into the spotlight by North Korea's announcement that it would soon launch a spy satellite -- which could also be used for military purposes.

Pyongyang notified Japan's coast guard on Sunday of the planned launch, which would violate UN sanctions on the North.

Seoul has said the North is receiving space-related assistance from Moscow in exchange for supplying weapons to Russian troops fighting in Ukraine.

Pyongyang first put a spy satellite into orbit in November 2023.

Yoon and Kishida urged the North to call off the launch, which the South Korean leader said would undermine "regional and global peace and stability" and warrant a "resolute" response from the international community if it goes ahead.

Li made no mention of the issue at a press conference following the summit.

China is a key trading partner and diplomatic ally of North Korea.

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