CIA Director Mike Pompeo appeared on "Fox News Sunday" to discuss North Korean nuclear development, which he said is proceeding at an "ever-alarming rate."

Pompeo said he could not get into specifics but said that North Korea's progress has gone on for decades. When host Chris Wallace pressed him about how close North Korea is to being able to hit the U.S. mainland, Pompeo said that it was alarming but hard to define.

"It's difficult to put a timeline to these things," Pompeo said. "But each time they test another missile, or if they should conduct a nuclear weapons test, they develop expertise, they expand the envelope, and so it is probably fair to say they are moving toward that at an ever-alarming rate."

Pompeo also said that the problem has been ongoing through previous U.S. administrations, but he argued President Donald Trump was making strides to effect change.

"They've been growing closer for two decades plus … Previous administrations haven't taken this on," Pompeo said. "President Trump has made it clear that it is his intention to protect the American people."

He pointed specifically to the U.N. sanctions against North Korea.

"You saw this past week we made real progress," Pompeo added. "My hat's off to the president, Secretary Tillerson, Ambassador Haley. They have united the world with sanctions against North Korea: a 15-0 vote. We've seen the Chinese say for among the first times, they believe the answer has to be a denuclearized peninsula. That's exactly the policy for the Trump administration."