Seoul Warns of Threat From Russia and North Korea

South Korean President Yoon Suk Yeol has warned the deepening relationship between Russia and North Korea poses a threat not only to South Korea but also to Europe.

"Military cooperation between Russia and North Korea poses a distinct threat and grave challenge to peace and security on the Korean Peninsula and in Europe," Yoon told Reuters news agency ahead of his departure for the U.S. for the July 10 to 11 NATO summit.

Yoon favors closer defense ties with other U.S. allies. He will attend the summit as an observer, along with his South Korean, Japanese, and New Zealand counterparts for the third straight year as NATO engages nonmember partners in the Asia-Pacific region, with an eye on China and North Korea. Australia will be represented by its Deputy Prime Minister and Minister of Defence Richard Marles.

South Korea, along with the United States and others, condemned the agreement signed last month by Russian President Vladimir Putin and North Korean counterpart Kim Jong Un, pledging military assistance if either country is attacked.

Yoon told Reuters that the future of South Korea's relationship with Russia depends entirely on Russia. He urged the country to decide which Korea better serves its interests.

"We categorically disagree with this approach," Putin's Press Secretary Dmitry Peskov said to Russian state media. Peskov added that Russia seeks good relations with both Koreas, saying that Pyongyang is a partner while Seoul has joined the anti-Russian sanctions. "How can we build good relations with countries that take a hostile position toward us?" Peskov added.

Tensions between North and South Korea are at their highest in decades. The suspension of a 2018 military agreement has led to the resumption of military exercises along the demarcation line separating the neighbors and near northwest border islands.

South Korea, which hopes to become the world's fourth-largest arms dealer by 2027, said it was mulling arming Ukraine after the Moscow-Pyongyang deal was inked. Putin warned such a move would be "a big mistake."

Yoon told Reuters that whether the South decides to provide Ukraine with weaponry depends on "the level and substance of military cooperation between Russia and North Korea." Yoon gave transfers of weapons and military technology as examples of areas Seoul will be watching.

North Korea has helped replenish Russian forces' stocks of artillery munitions and ballistic missiles. South Korean Defense Minister Shin Won-sik said at least 10,000 shipping containers have been transferred to Russia, enough to hold about 5 million artillery shells.

Asked about reports South Korea and the other three observer states would reach an agreement this week to boost cooperation with NATO, China's Foreign Ministry spokesperson Lin Jian on Monday called the security alliance a "Cold War legacy." He accused NATO of expanding beyond its mandate as a regional alliance and warned it against attempts "to destabilize the Asia-Pacific after it has done so to Europe."