South Korea has intelligence that North Korea has suffered losses among its troops dispatched to the war against Ukraine.

According to the National Intelligence Service on Monday, North Korean troops have been killed and wounded after they were confirmed to have been deployed in Russia’s Kursk region bordering Ukraine.

This is the first confirmation by the South Korean intelligence agency that there have been casualties among the North Korean contingent that entered the war alongside Russia.

In a Nov. 20 briefing to the National Assembly, the NIS said North Korean troops were believed to have been participating in battles on the front lines of the war.

“There is a lot of conflicting information floating around, so we are trying to determine the exact details,” the NIS was quoted as telling lawmakers.

Ukrainian media reports said over the weekend that North Korean soldiers appeared to have died in the aftermath of a Ukrainian attack using UK-supplied Storm Shadow missiles.

RBC-Ukraine, a Ukrainian news agency, reported Sunday that a Storm Shadow missile strike on the Kursk region killed about 500 North Korean soldiers and hurt three, including an interpretation officer.

The NIS said last month that Pyongyang was due to send about 10,900 troops, most of them from special forces, to fight alongside Russia. Many of the North Korean soldiers sent to the war were in their late teens or early 20s, according to the NIS.

The NIS added that large casualties were feared as the North Korean military was not trained to fight in a modern war.

The NIS revealed at the time that it had intelligence that North Korean generals such as Kim Yong-bok, deputy chief of the general staff for special forces operations, might be aiding Russia in the war.

The Institute for National Security Strategy, a think tank affiliated with the NIS, stated in a report Friday that Pyongyang may dispatch additional troops to help with Moscow’s cyber operations against Kyiv.

According to the INS report, North Korea and Russia were becoming more aggressive in their “cognitive warfare,” which is when false information is used to deliberately mislead the enemy.