U.S. Deputy Secretary of State Stephen Biegun has reaffirmed Washington's commitment to denuclearizing North Korea.
The State Department said Thursday that Biegun spoke on the phone the day before with Chinese Vice Foreign Minister Le Yucheng .
During that phone call, Biegun said Washington is committed to keeping the promises made with Pyeongyang at the first North Korea-U.S. summit in Singapore.
He also called on China to implement the UN Security Council sanctions on the regime.
President Trump thanked Beijing earlier this week for being "very helpful" to Washington in negotiations with Pyeongyang.