NATO Secretary-General Mark Rutte delivers a statement, after a meeting with a high-level South Korean delegation including top intelligence and military officials as well as senior diplomats, at NATO headquarters in Brussels, Monday. AP-Yonhap

North Atlantic Treaty Organization (NATO) Secretary-General Mark Rutte confirmed Monday that North Korean troops have been deployed to Russia's Kursk region, a front-line area in its conflict with Ukraine.

"Today I can confirm that North Korean troops have been sent to Russia and that North Korean military units have been deployed to the Kursk region," Rutte told reporters following a briefing from a high-level South Korean delegation.

The South Korean delegation, comprised of intelligence and government officials, attended a North Atlantic Council (NAC) meeting at the NATO headquarters in Brussels, for the briefing that was joined by ambassadors from NATO's Indo-Pacific partners -- Australia, Japan, New Zealand and South Korea. The NAC is NATO's main decision-making body.

The briefing on the deepening military cooperation between Pyongyang and Moscow came amid reports that Russia is deploying North Korean troops to front-line positions in its prolonged war with Ukraine.

Rutte stated that the deployment marked "a significant escalation of the DPRK's ongoing involvement in Russia's illegal war," referring to North Korea by its official acronym, the Democratic People's Republic of Korea.

"The deepening military cooperation between Russia and North Korea is a threat to both the Indo-Pacific and Euro-Atlantic security," Rutte said.

Ukraine earlier claimed that North Korean troops have started moving into the Kursk border region in western Russia, where Ukrainian forces launched an incursion in August.

"Today is for the intelligence briefing," First Deputy Director of the National Intelligence Service Hong Jang-won, who led the delegation, told reporters prior to attending the briefing.

Responding to a question from Yonhap News Agency about whether the NAC would consider sending a monitoring team, Hong stated that such decisions would not be made solely by the delegation.

The delegation's visit follows a request by Rutte for South Korea's briefing during a recent phone call with President Yoon Suk Yeol.

The delegation is also expected to hold talks with Rutte, and other senior NATO and European Union officials.

Discussions may cover support measures for Ukraine, potentially including the dispatch of South Korean intelligence personnel to Kyiv to monitor North Korean troop activity.

They may also touch on South Korea's options for aiding Ukraine, possibly reconsidering its policy on nonlethal aid in favor of providing military assistance. (Yonhap)