It is thought Kim Jong Un understands that phased efforts towards denuclearization “failed repeatedly,” U.S. Secretary of State Mike Pompeo said in an interview with Fox News Sunday, citing Pyongyang discussions with the North Korean leader last week.

The assessment comes despite Kim calling last week for “phased and synchronous measures (towards denuclearization) in a responsible manner” in his second meeting with Chinese President Xi Jinping.

“We’ve done trade-for-trade, moment-for-moment; you give me X, I give you Y; and it has failed repeatedly,” said Pompeo of the history of negotiations surrounding DPRK denuclearization