ISTANBUL

South Korea's main opposition leader has come out in opposition to a trilateral military alliance made up of his country, the US, and Japan, calling it “unnecessary” as it will likely deepen the mounting rivalry between two opposing power blocs.

Lee Jae-myung called for “pragmatic diplomacy” by South Korea, arguing that its alliance with Washington and its “strategic cooperative partnership” with Beijing are “not incompatible” given their mutual interests and robust trade ties, English daily the South China Morning Post reported on Wednesday.

South Korea boasts the world’s sixth-largest conventional military force, and the US is firmly committed to offering an “extended nuclear deterrence” to cope with nuclear-armed North Korea, he told members of the Foreign Media Club on Tuesday in the capital Seoul.

President Yoon Suk-yeol is set to visit Washington later this month for a summit with his US counterpart Joe Biden.

"Under these circumstances, a new war on the Korean Peninsula would mean the extermination of all lives,” said Lee, leader of the Democratic Party (DP) of Korea.

He added: “A trilateral military alliance that goes beyond the current military cooperation with the US and Japan is not necessary as it would only spark an equivalent alliance including the North, China, and Russia.”

Pentagon leak

Lee’s remarks come as South Korea Tuesday called information contained in leaked Pentagon documents “fabricated” though Seoul did not provide more details.

South Korea on Monday said it will seek “appropriate measures” from the US after spying revelations came to light in recently leaked Pentagon documents.

The opposition DP had urged the government to “immediately demand clear information” from Washington on reports about alleged “attempts by the US to eavesdrop on South Korean officials” contained in the leaked documents.

While Seoul initially had said it plans to “request appropriate measures from the US, if necessary,” it later called the documents false.

The US Justice Department and Pentagon are investigating after alleged screenshots of classified US and NATO documents regarding the Ukraine war and other issues emerged on social media.

There were reportedly alleged “attempts by the US to eavesdrop on South Korean officials” in the leaked documents.

On Wednesday, the DP accused the Yoon administration “of taking a submissive attitude” toward the US over suspicions that US intelligence agencies eavesdropped on South Korea and other allies, according to Yonhap News.

“Are there bad intentions and good intentions in eavesdropping?" said Park Jie-won, an adviser to the DP and a former National Intelligence Service chief. “The act itself is illegal and bad.”

Yoon is also facing opposition to normalizing relations with Japan as the DP criticized his visit to Japan last month and called it a “move against South Korea's national interest.”

The opposition also opposed the Yoon government's decision to establish a public foundation in Seoul to compensate victims of Japanese forced labor and sexual exploitation during World War II.

*Aamir Latif contributed to this report from Pakistan.