South Korea's intelligence agency says North Korea is set to send up to 12,000 troops to fight alongside Russia in Ukraine, which Seoul has described as a 'serious security threat' “.
Ukrainian President Volodymyr Zelensky earlier said that 10,000 North Korean troops could join the war, based on intelligence information.
South Korean President Yoon Suk Yeol called for a security meeting on Friday and said the international community must respond with “all available means.”
This comes as evidence mounts that North Korea is supplying munitions to Russia, as recently demonstrated by the recovery of a missile in Ukraine's Poltava region.
Moscow and Pyongyang have also deepened their cooperation in recent months. Last week, North Korean leader Kim Jong Un greeted Russian President Vladimir Putin on his birthday, calling him his “closest comrade.”
Friday's security meeting was attended by key officials from South Korea's National Security Office, the Ministry of National Defense and the National Intelligence Service, Yoon's office said.
“(The participants) decided not to ignore the situation and to respond to it jointly with the international community using all available means,” the statement said.
The National Intelligence Service's allegation comes days after Ukrainian military intelligence sources said the Russian military was training a unit made up of North Koreans.
The BBC has contacted the NIS for comment.
Earlier this week, Putin introduced a bill aimed at ratifying a military pact he made with Kim, which promises that Russia and North Korea will help each other in the event of “aggression” against one or the other country.
A military source in Russia's Far East told BBC Russia this week that “a number of North Koreans arrived” and were stationed at one of the military bases near Ussuriysk, north of Vladivostok.
However, some military experts believe that Russian military units will have difficulty integrating North Korean troops into their front lines.
Aside from the language barrier, the North Korean military has no recent experience in combat operations, they said.
“They could guard certain sections of the Russian-Ukrainian border, which would free up Russian units to fight elsewhere,” said Valeriy Ryabykh, editor-in-chief of the Ukrainian publication Defense Express.
“I exclude the possibility that these units will immediately appear on the front line.”
Additional reporting by Jake Kwon and Hosu Lee in Seoul
