Washington (CNN) President Donald Trump on Thursday morning suggested that some of the elements of his potential summit later this year with North Korean leader Kim Jong-Un are up in the air.

"It could be that I walk out quickly, with respect, but it could be. It could be that maybe the meeting doesn't even take place. Who knows?" Trump told Fox News' "Fox and Friends" during a half-hour call-in appearance.

The President said in the past, North Korea-US relations were "very, very nasty you know with little Rocket Man and with the buttons." But now, he said, "they want to meet."

Trump added that there are three or four possible dates for the summit and confirmed CNN's reporting that five locations are currently under review for the meeting.

The agreement to a joint summit between the two world leaders came after CIA director and now secretary of state nominee Mike Pompeo paid a visit to Kim in North Korea.

Read More