U.N. envoy Martin Griffiths, who has been leading efforts to restart negotiations last held in December 2018 to end the conflict, told the Security Council the U.S. move could have “a chilling effect” on efforts to bring the parties together and should be revoked on humanitarian grounds. emen’s Houthi movement will not walk away from peace talks with the United Nations and Saudi Arabia despite the U.S. decision to designate the Iran-aligned group as a foreign terrorist organisation, the Houthi chief negotiator told Reuters.