This story has been updated to include expert comment.

U.S. Secretary of State Rex Tillerson on Friday urged African leaders to do more on enforcing North Korea sanctions, during the Ministerial on Trade, Security, and Governance in Africa held in Washington.

Tillerson asked the group to limit their diplomatic relations with the DPRK, saying the U.S. was looking for help from its global partners on security issues.

“We appreciate the statements condemning the DPRK missile launches that many of your governments have made. But all nations must act to implement UN sanctions in full and cut off all UN-proscribed ties,” Tillerson