Washington (CNN) President Donald Trump said Tuesday that North Korean dictator Kim Jong Un -- the man he once mocked as "Little Rocket Man" -- "has really been very open and I think very honorable based on what we are seeing" as the two gear up for an anticipated face-to-face meeting in the coming weeks.

He didn't expand further when asked to explain his comment that Kim is an "honorable" person, sidestepping the question.

Trump said he is looking forward to meeting Kim "very soon" and indicated the North Koreans are pressing for talks to begin immediately.

"We are going to be having a meeting with Kim Jong Un and that will be very soon. We have been told directly that they would like to have the meeting as soon as possible," Trump said.

"We're having very good discussions," he added.

The White House has continued its push to temper expectations around a potential summit -- saying the US will not negotiate any concessions until Pyongyang takes concrete steps toward dismantling its nuclear and missile programs.

White House press secretary Sarah Sanders emphasized on Monday that the US is "not naive in this process" and is "not going to make mistakes from previous administrations."

"We're not going to take the North Koreans at their word. The maximum pressure campaign is going to continue until" there are concrete steps toward denuclearization," she said. "We're not naive in this process. We've seen some steps in the right direction but we have a long way to go."

Very honorable?

While Trump has clearly softened his rhetoric ahead of a potential meeting with Kim, characterizing the North Korean's intentions as "very honorable" was an interesting choice of words considering the regime's troubling human rights history and reputation for ruthlessness.

"North Korean citizens are regularly subjected to arrest for trifling crimes and sentenced to labor camps," according to a recent CNN op-ed by John Sifton , the Asia advocacy director at Human Rights Watch, who noted a 2014 UN report that found many die in prison from beatings, malnourishment or untreated sickness, among other causes.

Stories of Kim's brutal executions have also filtered out since he took power in 2011 and indicate that he has purged hundreds of senior officials in his own party.

In 2016, North Korea's top education official, Kim Yong Jin, was executed by firing squad after he exercised a "bad attitude" at the country's Supreme People's Assembly.

In May 2015, Kim had his defense minister, Hyon Yong Chol, killed with an anti-aircraft gun at a military school in Pyongyang, in front of an audience.

South Korean intelligence officials say Kim also directly ordered the killing of his half brother Kim Jong Nam -- a claim North Korea vehemently denies.

Trump condemned North Korea's "brutal regime" last year after the death of Otto Warmbier -- a 22-year-old American student who was detained for 17 months in North Korea, where his family believes he was tortured into a vegetative state.

Three American citizens -- Kim Hak-song, Kim Sang-duk and Kim Dong Chul -- are still being held by the North Korean government.

A US official said last week that Trump's secretary of state nominee, Mike Pompeo, had raised the issue of the detained Americans when he secretly met with Kim in Pyongyang earlier this month to lay the groundwork for direct talks between Trump and Kim about North Korea's nuclear weapons program.

Trump himself has said the administration is "fighting very diligently" to get the US citizens back and that there is a "very good dialogue," but whether those talks are directly linked to negotiations over North Korea's nuclear program remains unclear.

'No concessions'

Pressed on his definition of "denuclearization" in North Korea, Trump said Tuesday that he wanted to see Pyongyang get rid of all its "nukes."

"They get rid of their nukes. It means they get rid of their nukes," he said, adding it would be easy to strike a "simple deal" with North Korea but that he was aiming higher.

"It would be very easy for me to make a simple deal and claim victory. I don't want to do that. I want them to get rid of their nukes," he added.

Trump repeated his vow to walk out of the meeting with Kim should it fall short of his expectations and said he has made no concessions to North Korea ahead of the possible talks.

"Maybe it will be wonderful. And maybe it won't," he said. "And if it's not going to be fair and reasonable and good, unlike past administrations, I will leave the table."

"We have made no concessions, other than the fact that meeting is a great thing," Trump said at a news conference.

On Sunday, Trump also responded to criticism that Pyongyang is getting more out of the talks than Washington is, declaring that the US has not "given up anything."

"Wow, we haven't given up anything & they have agreed to denuclearization (so great for World), site closure, & no more testing!" Trump tweeted.

The President followed up with a second tweet that said, "We are a long way from conclusion on North Korea, maybe things will work out, and maybe they won't -- only time will tell."