US President Donald Trump should not meet with North Korean leader Kim Jong-un unless the communist nation gives up its nuclear weapons program, former US Secretary of State Condoleezza Rice said Monday.

Rice also said on CBS' "This Morning" that Kim is "reckless and maybe even a little unhinged."

Asked for comment on Trump's remarks that he would be "honored" to meet with the North's leader if circumstances are right, Rice said, "The president of the United States can't meet with Kim Jong-un, and certainly not under these circumstances."

"There may come a day if North Korea gives up its nuclear weapons program and so on and so forth, and having North Korea back in the community of states or in the community of states would be worthwhile," she said.

Rice said the North appears to be trying to show it's powerful.

"Clearly, they are, I think, trying to send a message that they are powerful, they are strong, they can make the United States suffer, and this is not a situation that any American president can ultimately tolerate. Something has to be done about that nuclear program," she said.

Rice said she agrees with Trump's assessment that Kim is a "smart cookie."

"Well, he is a smart cookie. He wouldn't have survived that long. Let's be clear: he obviously knows what he's doing," she said.

Rice also said China is the key to the North Korea problem.

"We've got to change their calculation. Right now, they seem more worried about the potential collapse of the regime and doing hard things to the regime than about a nuclear North Korea. I think that's what the administration is trying to do is to change their calculus so that the Chinese see that if they don't deal with the North Koreans, we will," she said. (Yonhap)