Russia sent home nearly 20,000 North Koreans working there in 2018 and China repatriated more than half of them, according to unpublished reports by Moscow and Beijing to the United Nations Security Council, Reuters reports. The one-page reports, viewed by Reuters on Tuesday, were submitted to the council’s North Korea sanctions committee in compliance with a 2017 resolution demanding the repatriation of all North Korean workers by the end of this year—a measure put in place to prevent them from earning foreign currency for leader Kim Jong Un’s authorities. The United States has said it believed Pyongyang was earning more than $500 million a year from nearly 100,000 workers abroad, of which about 30,000 were in Russia and 80,000 were in China. The U.N. Security Council has continued to toughen sanctions on North Korea since 2006 to squelch funding for Pyongyang’s nuclear and ballistic missile programs. President Trump and Kim have had meetings twice in the past year to discuss denuclearization, the latest of which ended abruptly with little headway.