In the first few days of the Biden-Harris administration, a top U.S. diplomat has called for greater sanctions enforcement against North Korea in order to stymie inflows of cash that could support the country’s nuclear program.

Linda Thomas-Greenfield, a longtime diplomat who has been nominated as the U.S. ambassador to the United Nations, said that Donald Trump’s administration failed to properly collaborate with allies and other countries to stop North Korea from illegally making money abroad.