One year after North Korean leader Kim Jong Un's half brother was assassinated at Kuala Lumpur's airport, Malaysia is further downgrading once-close ties with Pyongyang, sources familiar with the government's plans said.

Kim Jong Nam was assassinated on Feb. 13, 2017 when two women smeared his face with VX nerve agent — which the U.N. lists as a weapon of mass destruction. The women claim they were tricked into believing they were part of a reality show, but the U.S. and South Korea say the murder was orchestrated by Pyongyang.

The brazen killing came as North Korea was starting to accelerate its missile tests and countries around the world came under mounting pressure to enforce ever-tightening U.N. sanctions against Pyongyang.