Sanctions to stay till N.Korea takes irreversible steps

United Nations sanctions against North Korea should remain in place until North Korea takes concrete, irreversible steps toward denuclearization, the defence chiefs of South Korea and the United States said on Thursday.

U.S. Defence Secretary Jim Mattis and his counterpart Song Young-moo also agreed to explore additional confidence-building measures while North Korea continues the dialogue "in good faith," according to a joint statement released by Seoul's defence ministry after their talks in Seoul.