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South Korean President Yoon Suk Yeol addresses the United Nations General Assembly at the UN headquarters on September 20 in New York City.
CNN  — 

South Korean President Yoon Suk Yeol warned on Wednesday that his country and its allies “will not stand idly by” if North Korea receives Russian help to boost its weapons of mass destruction – just days after the leaders of the two nuclear-armed nations held a closely watched summit.

North Korean leader Kim Jong Un traveled to Russia last week for a meeting with President Vladimir Putin. Ahead of the meeting US officials warned that the two leaders could strike a deal that would provide weapons for Moscow to use in its grueling war against Ukraine – and that could see sanction-hit Pyongyang gain access to vital Russian technology.

That has alarmed South Korea, a US treaty ally.

Speaking at the United Nations General Assembly in New York, Yoon declared: “While military strength may vary among countries, by uniting in unwavering solidarity and steadfastly adhering to our principles, we can deter any unlawful provocation.”

He also called to reform the UN Security Council – of which Russia is a member – saying such a move “would receive a broad support” if Moscow did supply Pyongyang with information in exchange for weapons.

“It is paradoxical that a permanent member of the UN Security Council, entrusted as the ultimate guardian of world peace, would wage war by invading another sovereign nation and receive arms and ammunition from a regime that blatantly violates UN Security Council resolutions,” Yoon said.

He added that if North Korea “acquires the information and technology necessary to enhance its (weapons of mass destruction) capabilities in exchange for supporting Russia with conventional weapons, the deal will be a direct provocation, threatening the peace and security of not only Ukraine, but also the Republic of Korea,” the president added.

US Secretary of State Antony Blinken echoed Yoon’s call to reform the UN Security council during his address at the UNGA, and accused Russia of seeking weapons from North Korea.

Kim’s trip to see Putin was his first overseas visit since the coronavirus pandemic.

The two leaders met for five hours, holding what the Kremlin called “very substantive” discussions.

But little is known of what went on behind closed doors; the two sides held no press conference, issued no communique, and have not publicly announced any deals.

Kremlin spokesman Dmitry Peskov said the two leaders did not sign any agreements during their talks.

Still, the talks signaled closer relations between the two countries, both of which face international isolation – Russia for its invasion of Ukraine and North Korea for its nuclear weapons and ballistic missile program.

As the war drags on, Moscow is desperate for fresh supplies of ammunition – while North Korea ramps up its weapons testing program, eager to advance its nuclear ambitions.