South Korea 's Yonhap News Agency said North Korea might be using a vertical cold-launch system to fire the missiles. The system, which is commonly associated with submarine- and ship-based weapons, ejects a missile from its container before the missile ignites midair.

North Korea is likely preparing to send additional troops to Russia after suffering heavy losses in battles against Ukrainian forces, South Korea's military said Friday.

The South Korean military reports on North Korea's plans to send additional troops to Russia, attributing this decision to numerous casualties. North Korea is preparing to reinforce its military presence in Russia.