Newly minted U.S. Secretary of State Mike Pompeo said Sunday he has spoken with North Korean leader Kim Jong Un about how the isolated country might relinquish its nuclear arsenal and what a "complete, verifiable, irreversible mechanism might look like."

Asked on ABC News' "This Week" about his clandestine visit to Pyongyang over Easter weekend to lay the groundwork for U.S. President Donald Trump's planned meeting with Kim, Pompeo, who prior to being sworn in as the top U.S. diplomat on Thursday had been serving as CIA chief, called the trip a "productive one," adding that there is "a real opportunity" for the two leaders to strike a deal.

Pompeo, in his most extensive comments yet on the secret meeting with Kim, said the two had discussed a number of issues that could be achieved at the summit.