SEOUL, Jan. 9 (UPI) -- North Korea is gaining crucial military experience and equipment by sending troops to Russia, a U.S. official warned the United Nations, making the regime a growing threat to neighboring countries. More than 12,000 North Korean soldiers have been deployed to Russia to aid Moscow in its war against Ukraine , U.S. Deputy Ambassador to the United Nations Dorothy Shea told a U.N. Security Council briefing Wednesday. Advertisement Pyongyang has also sent more than 20,000