U.S. President Donald Trump will hold a second summit with North Korean leader Kim Jong Un "in the next couple of months," White House national security adviser John Bolton indicated in a radio interview aired Friday.

"We'll see a meeting, I think, between Chairman Kim and President Trump sometime in the next couple of months," Bolton said, suggesting it may not take place by the end of the year.

Bolton made the remark Thursday, two days after Trump said he wants to meet Kim again after the U.S. midterm elections on Nov. 6, and that he is considering three or four possible locations for the event.

(Kim and Trump shake hands during their historic U.S.-DPRK summit in Singapore in June)[Getty/Kyodo]

Speaking in a nationally syndicated radio show hosted by Hugh Hewitt, Bolton stressed the need for North Korea to denuclearize "completely and irreversibly."

"If they do that and walk through the door" that Trump opened during the first summit with Kim in June in Singapore, "the future could be very different for the North Korean people," he said.

Bolton said Trump is "optimistic" about his diplomacy toward North Korea, but that the president "does not have stars in his eyes about this."

"Neither does Mike Pompeo, neither does Jim Mattis, neither do I," he said, in reference to the secretaries of state and defense.

Bolton said the combination of the potential use of military force against North Korea and the "maximum" pressure campaign with tightened sanctions has brought Kim to the table for denuclearization negotiations.

However, Pyongyang has yet to take credible action to dismantle its nuclear weapons and missile programs despite Kim pledging in the first-ever U.S.-North Korea summit to work toward "complete" denuclearization of the Korean Peninsula.

Separately, CBS News reported that during Pompeo's visit to Pyongyang last Sunday for talks with Kim, North Korean officials asked a CBS reporter -- the only journalist accompanying Pompeo on the trip -- whether she thinks Trump's Republican Party would win the November elections.

The reporter, Kylie Atwood, on Thursday quoted one North Korean official as calling Trump "generous." Another North Korean official, speaking through a translator, hailed the president's dealings with North Korea, saying the two countries "wouldn't be here without Trump."

Atwood asked North Korean officials about the next Trump-Kim summit, and the officials replied it would be great to have it in Pyongyang, according to the report.