US Defense Secretary Jim Mattis has said that he still has confidence in diplomatic efforts on North Korea. “We will continue to work diplomatically, we will continue to work through the UN, the UN Security Council, and we will be unrelenting in that,” Mattis said before the start of a meeting with Libyan Prime Minister Fayez al-Seraj at the Pentagon on Thursday. “At the same time, our diplomats will speak from a position of strength because we do have military options,” Reuters quoted him as saying.