Yonhap earlier on Friday reported that the agency had confirmed that a North Korean soldier dispatched to fight for Russia had been captured by Ukrainian forces.
"Through the exchange of information in real time with the intelligence organisation of a friendly nation, we confirmed the capture of a wounded North Korean soldier and we plan to thoroughly examine the subsequent development," said South Korea's National Intelligence Service in a brief statement.
South Korea's confirmation came after Ukrainian military outlet Militarnyi reported on Thursday that Ukrainian forces had captured a North Korean soldier during an operation in the Kursk region on Russia's western front line, though it did not specify when the incident had taken place.
"The special forces group carried out an operation to destroy the enemy in the Kursk sector. In addition to the successful completion of the task, there were also trophies, prisoners, including a North Korean mercenary, and an armoured vehicle," the Ukrainian outlet's text read.
According to South Korean officials, about 11,000 North Korean soldiers have been sent to Russia so far and there are signs of preparations for further deployment of troops and military equipment.
Ukrainian President Volodymyr Zelenskyy said earlier this week that the number of North Korean soldiers killed and wounded in Kursk exceeded 3,000, according to preliminary data.
"There is a risk that North Korea will send more soldiers and military equipment to the Russian army. We will have a response to this," Zelenskyy also wrote on Telegram.
South Korea says about 11,000 North Korean soldiers have been sent to Russia for service in Ukraine. (AP PHOTO)
The risk of destabilisation on the Korean peninsula and in neighbouring regions and waters increases proportionally to the growth of cooperation between Moscow and Pyongyang and the spread of Russian military technology and experience, the Ukrainian president said. He called for "effective pressure" against Russia and North Korea.
North Korean drones could soon be tested by combined Russian and North Korean forces in Russia's Kursk region, said Andri Kovalenko, head of the Centre for Countering Disinformation at the National Security and Defence Council, on Monday.