In an interview with CBS, the chief US diplomat noted the six tests of short-range ballistic missiles that North Korea has conducted in recent weeks, and appeared to diverge slightly with President Donald Trump, who have dismissed the tests as unthreatening and insignificant.

"I wish they would not do that," Pompeo said of the tests.

He added that he hopes that North Korean leader Kim Jong Un will agree to resume negotiations, after three face-to-face meetings with Trump.

"We haven't gotten back to the table as quickly as we would have hoped," Pompeo said.

"We have been pretty clear all along. We know there will be bumps along the way."

He said the State Department's special representative for North Korean negotiations, Stephen Biegun, is in Asia this week.

"We hope Chairman Kim will come to the table, get a better outcome. It will be better for the North Korean people. It will be better for the world," Pompeo said.