National security adviser John Bolton says that the U.S. is not yet certain whether North Korea will actually give up its weapons of mass destruction.

"Well, I don't think we know at this point," Bolton told host Margaret Brennan on CBS News' "Face the Nation" on Sunday when asked whether he thought North Korean leader Kim Jong Un is serious about negotiating away his arsenal. "I think if he has made a strategic determination that North Korea would be better off without nuclear weapons then I think we've got something to talk about and I think the president would be eager to capitalize on the opportunity."

Ahead of a potential meeting between President Trump and Kim, Bolton indicated that inspections of nuclear sites will be necessary before U.S. sanctions will be relieved. He brought up Libya's decision to surrender its nuclear program, a process that was monitored by U.S. and allied officials.

"I think we're looking at the Libya model of 2003, 2004," Bolton said. "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."

According to Bolton, negotiations between the U.S and North Korea would also involve Pyongyang's chemical weapons program, its abductions of foreign citizens and the status of three American citizens currently being held in the country.

"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 said.

Bolton also said that North Korea's willingness to negotiate is directly attributable to Mr. Trump's "pressure campaign" against the country. However, he also cautioned that North Korea had pledged to end its nuclear program before, meaning some skepticism is warranted about Kim's intentions.

"They've said that they're going to give up nuclear testing and ballistic missile testing," Bolton said. "They haven't conducted any recently. That's true. That 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. We've seen this in other contexts as well. President Trump is determined to see this opportunity through. Hopeful that we can get a real breakthrough, but we're not naive in the administration and a lot's going to ride on this meeting with Kim Jong Un."

Turning to the Iran nuclear deal, which Mr. Trump may soon decide to leave, Bolton reiterated that withdrawing from the deal is under consideration. At the same time, he would not rule out the possibility that the deal could be fixed, saying that the decision was up to the president.

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

Bolton added that while he stuck by comments he made that were deeply critical of the nuclear deal, he is now a presidential adviser, meaning that it's his job to present Mr. Trump with options on how to proceed.