North Korea sends foreign minister to Russia as its troops train to fight in Ukraine

North Korea said Tuesday its top diplomat is visiting Russia, in another sign of their deepening relations as rival South Korea and western nations say the North has sent thousands of troops to support Russia's war in Ukraine.

North Korea said Tuesday its top diplomat is visiting Russia, in another sign of their deepening relations as rival South Korea and western nations say the North has sent thousands of troops to support Russia's war in Ukraine.

North Korea's official Korean Central News Agency said a delegation led by Foreign Minister Choe Son Hui departed for Russia on Monday, but didn't specify the purpose of the visit. In a closed-door hearing at South Korea's parliament, the South's spy agency said Choe may be involved in high-level discussions on sending additional troops to Russia and negotiating what the North would get in return, according to Lee Seong-kweun, a lawmaker who attended the meeting.

The announcement of Choe's visit came hours after the Pentagon said North Korea has sent about 10,000 troops to Russia, who are expected to arrive in battlefields in Ukraine within "the next several weeks."

South Korean and western leaders have expressed concern that North Korean involvement could help prolong Russia's aggression in Ukraine, and that Russia may offer technology in return that could advance the threat posed by North Korea's nuclear weapons and missile program.

Pentagon spokesperson Sabrina Singh told reporters Monday that some of the North Korean soldiers have already moved closer to Ukraine and were believed to be heading for the Kursk border region, where Russia has been struggling to push back a Ukrainian incursion.

South Korea's National Intelligence Service told lawmakers it's examining the possibility that some groups of North Korea's military personnel in Russia, including generals or other high-ranking officials, may have already moved to frontline areas. The spy agency also said the two sides appear to be struggling to resolve communication issues although the Russian military is training North Korean troops on Russian military terminology, Lee said.

The agency said space-based reconnaissance is an area where North Korea is likely receiving Russian help. It said North Korea may be acquiring advanced components from Russia as it prepares to launch another military reconnaissance satellite following a failed attempt in May, said Park Sun-won, another lawmaker who attended the hearing.