U.S., North Korea clash at U.N. arms forum on nuclear threat

By Stephanie NebehayGENEVA (Reuters) - North Korea and the United States accused each other on Tuesday of posing a nuclear threat, with Pyongyang's envoy declaring it would never put its atomic arsenal up for negotiation.The debate at the United Nations began when the U.S. envoy said President Donald Trump's top priority was to protect the United States and its allies against the "growing threat" from North Korea.