The U.S. is looking for alternatives to the expert panel monitoring North Korea sanctions both “inside and outside the U.N.,” Washington’s ambassador to the U.N. said Wednesday, assessing that Russia and China will not agree on a deal to save the Panel of Experts before its mandate ends on April 30.

Linda Thomas-Greenfield delivered the remarks at a press conference in Seoul to mark the end of her visit to South Korea, where she met with officials and DPRK escapees and visited the Demilitarized Zone.