National Security Adviser John Bolton discussed nuclear negotiations with North Korea on Sunday’s edition of Face the Nation on CBS.

Bolton’s position was that dictator Kim Jong-un’s promises and charming publicity stunts count for nothing; all that matters is what North Korea actually does to stabilize the Korean peninsula and commit to verifiable denuclearization.

Bolton said it remains to be seen whether Kim has concluded denuclearization is in his best interests. He gave President Donald Trump credit for applying the pressure needed to create the current diplomatic opening to Pyongyang, and noted that world leaders from South Korea and Japan to Europe have done likewise, but stressed that North Korea must now take concrete steps to prove that its overtures are more than just a time-wasting diplomatic mirage.

“I think we’re looking at the Libya model of 2003, 2004,” said Bolton, naming an example of effective denuclearization that his administration might not want Kim Jong-un to dwell on at length, given how things worked out for the dictator in question. He later clarified that the level of access Libya permitted to American and British inspectors to verify denuclearization is what he wants North Korea to emulate. He also pointedly stated that oversight from “international mechanisms” was not an acceptable substitute for inspectors from the U.S. and U.K.

“We’re also looking at what North Korea itself has committed to previously and, most importantly, I think going back over a quarter of a century to the 1992 joint North-South denuclearization agreement where North Korea committed to give up nuclear weapons and committed to give up uranium enrichment and plutonium reprocessing,” Bolton continued, stressing that the Trump administration will not take Kim’s verbal guarantees and paper commitments seriously.

“We want to see real commitment. We don’t want to see propaganda from North Korea,” he declared.

“Now we’ve got other issues to discuss as well; their ballistic missile programs, their biological and chemical weapons programs, their keeping of American hostages, the abduction of innocent Japanese and South Korean citizens over the years. So there’s a lot to talk about,” Bolton added.

The national security adviser was guardedly optimistic about North Korea’s lack of provocative nuclear or missile tests in recent months, noting that it “could be a very positive sign or it could be a sign that they’ve reached the level of development where they don’t need testing now.”

Bolton said President Trump is “ready to go” on with meeting with Kim Jong-un, but the date and location for the summit have not been “pinned down yet.”

Referring to the three Americans still held prisoner by North Korea, Bolton said they are “at the top of the president’s mind” and strongly implied that North Korea should consider releasing them even before negotiations begin, as a “demonstration of their sincerity.”

Bolton also discussed the Iran nuclear deal—a little over 24 hours before Israeli Prime Minister Benjamin Netanyahu would figuratively drop a bomb on it by revealing the Iranians continued secretly working on literal bombs after the deal was signed. The thrust of his remarks was that he remains strongly critical of the deal but sees his job as presenting President Trump with “advice” and “options,” rather than deciding the fate of the deal himself.

“I think it’s a question of the president being open to make the final decision. It’s the job of his advisers to give advice. He’s the decision maker,” Bolton said.

He refused to discuss “hypotheticals” about the fate of the Iran nuclear deal but confirmed that “certainly withdrawal is under consideration.” He stressed that President Trump’s views on the deal have been “uniformly consistent and unvarying since the campaign of 2016.”