washington — North Korea is likely anticipating Russian technical assistance to perfect its nuclear and missile programs in exchange for sending its troops to support Russia in the Ukraine war, U.S. experts say. On Wednesday, the U.S. government confirmed for the first time the presence of at least 3,000 North Korean troops in Russia. Last Friday, South Korea’s intelligence agency said North Korea had sent 1,500 special forces troops to Russia for training and likely deployment for combat in the war in Ukraine. Seoul has expressed grave concerns about the development. “North Korea will expect a generous payoff from Moscow