U.S. Secretary of State Antony Blinken talks to the press before his meeting with NATO chief at NATO's headquarters during his one-day visit for Ukraine talks with NATO chief, European Union diplomacy boss and Ukraine's Foreign Minister in Brussels, Nov. 13. AFP-Yonhap

U.S. Secretary of State Antony Blinken warned Wednesday that the deployment of North Korean troops alongside Russian forces fighting on the Ukrainian border demanded a "firm response."

Blinken said he discussed during Brussels talks with NATO chief Mark Rutte the fact that North Korean forces have been "injected into the battle, and now, quite literally, in combat which demands and will get a firm response." (AFP)