"If Chairman Kim has reneged on the commitments he made to President Trump it's deeply disappointing," Pompeo told CBS television after North Korean leader Kim Jong Un declared an end to moratoriums on nuclear and intercontinental ballistic missile tests and threatened a demonstration of a "new strategic weapon" soon.

"We have lived up to our commitments. We continue to hold out hope that he will live up to his," the top US diplomat said.

"President Trump has taken an approach where we have tried to create a diplomatic pathway. We hope that the North Koreans will reconsider, that they will continue down that pathway.... We want peace not confrontation."