President Yoon Suk Yeol speaks during a meeting at the presidential office in Yongsan District, Seoul, Oct. 29. Yonhap

President Yoon Suk Yeol said Tuesday that North Korea's troop deployment in Russia constituted security threats to both South Korea and the world, denouncing what he calls "illegal" military cooperation between Pyongyang and Moscow.

Yoon made the remark during a Cabinet meeting amid North Korea's deployment of its troops in western Russia, with all signs suggesting that the North's troops may soon be ready for battlefield deployment against Ukraine forces.

"This illegal military cooperation between Russia and North Korea is a significant security threat to the international community and could pose a serious risk to our national security," Yoon said.

"With the war in Ukraine going on for three years, North Korea has deployed troops to Russia beyond providing weapons," Yoon said.

"We must thoroughly assess all possibilities and prepare countermeasures. I urge everyone to engage in risk management with a heightened sense of vigilance," he added.

Yoon also urged the government to proactively respond to external uncertainties ahead of the U.S. presidential election next week and geopolitical risks in the Middle East following Israel's attacks on Iran over the weekend.

"It is crucial to respond in a timely manner to ensure that our economy is not adversely affected by issues like supply chains, oil prices and exchange rates," Yoon said.

Yoon, in a phone call with European Commission President Ursula von der Leyen on Monday, said the deployment of North Korean troops to the front lines of the war in Ukraine may come sooner than expected.

Seoul's spy agency previously anticipated about 10,000 North Korean soldiers to be deployed on the battlefield by December.

On Monday, North Atlantic Treaty Organization Secretary General Mark Rutte received a briefing from a South Korean delegation and confirmed North Korean troops have been deployed to Russia's Kursk region near the border with Ukraine.

Russian President Vladimir Putin has neither denied nor confirmed the deployment, but said his government takes the "comprehensive strategic partnership" treaty with Pyongyang seriously, which includes mutual defense provisions. It was signed in June and ratified by Russian lawmakers last week. (Yonhap)