In a sharp rebuke to President Donald Trump, the parents of Otto Warmbier blamed Kim Jong Un for the death of their son from injuries suffered in a North Korean prison and said "no excuse or lavish praise can change that."

"Kim and his evil regime are responsible for the death of our son, Otto," Fred and Cindy Warmbier said in a statement issued Friday by their lawyer. "Kim and his evil regime are responsible for unimaginable cruelty and inhumanity."

The Warmbiers did not mention Trump by name, but within hours, the president tweeted that he had been "misinterpreted" over the issue.

He said he holds North Korea responsible. In Hanoi, Trump said that Kim told him he had not been aware of Otto's treatment and the president said he would "take (Kim) at his word."

Otto Warmbier, then a 21-year-old student at the University of Virginia, was arrested in January 2016 during a five-day trip to North Korea for allegedly trying to steal a propaganda poster from his Pyongyang hotel. He was sentenced to 15 years of hard labor.

After 17 months in prison, Otto was released in June 2017 in a vegetative state and flown back to the United States where he died less than a week later with a severe neurological injury.

The couple said they had refrained from any comments earlier out of respect for the second summit between Trump and Kim that wrapped up Thursday in Hanoi.

Profile:Who was Otto Warmbier — the student released from North Korea?

Trump, in response to a question from reporters, had said Thursday that he did not believe that Kim knew about Warmbier's condition or treatment during his imprisonment.

"He felt badly about it," Trump said, referring to Kim. "He knew about it very well, but he knew it later."

The president went on to say: "He tells me that he didn't know about it, and I will take him at his word."

Trump also took pains to praise Kim as his "good friend."

In their statement, which was released within hours after Trump's remarks, the Warmbiers, who live in Cincinnati, said, "Now we must speak out."

Republican Sen. Rob Portman, who represents the Warmbier's home state of Ohio, also spoke out strongly to assess blame in the student's death. “We must remember Otto, and we should never let North Korea off the hook for what they did to him,” Portman said.

White House counselor Kellyanne Conway addressed the issue earlier in an appearance on FOX News Channel’s America’s Newsroom.

Conway said she had spoken to Trump about the issue and that "the president agrees with the Warmbier family and holds North Korea responsible for Otto Warmbier's death. He's said that time and again."

"But the president is talking about Chairman Kim did not know what happened to Otto at the time of when it happened," she added."and so of course he holds North Korea responsible."

Conway said Trump has "deep affection and shares the grief" of the Warmbier family and "that will never end."

"But Chairman Kim did not know the — what the president is saying is that there's no indication Chairman Kim knew what happened to Otto Warmbier when it happened," "she said. "It's after he was returned here to the United States that we all learned of his very sad and frankly unforgivable state.”

President Trump on Otto Warmbier:From 'brutal regime...we'll handle it' to 'I will take (Kim) at his word.'

The Warmbiers had attended the 2018 State of the Union address at Trump's invitation. In the president's speech, he called the family "powerful witnesses" to North Korea's horrors as the Warmbier family watched from a guest box in the U.S. House of Representatives.

The Warmbier family received two standing ovations during the speech. Fred and Cindy stood next to first lady Melania Trump and wept as they acknowledged the cheers.

"You are powerful witnesses to a menace that threatens our world, and your strength inspires us all," Trump said. "Thank you very much."

Former New Mexico governor Bill Richardson, a Democrat and a former ambassador to the United Nations who tried in the past to negotiate Warmbier's release, said on MSNBC Thursday that it was "dispiriting" and "disappointing" that Trump would side with Kim over American intelligence.

Rosa Park, director of programs and editor at The Committee for Human Rights in North Korea, described North Korea as a totalitarian dictatorship where nothing escape'sKim's eye.

"Anything that the leadership does has to be approved by the man at the top," sPark said.

In December, a federal judge awarded the Warmbiers $500 million in punitive and compensatory damages, ruling that Otto was tortured in North Korea.

U.S. District Court Chief Judge Beryl A. Howell found that North Korea "deliberately caused Otto's brain damage, which resulted in his death."

It’s unclear if the Warmbiers will actually receive any money from North Korea from the judgment.

Carl Tobias, professor at the University of Richmond School of Law, said Monday that getting the North Korean government to cooperate would be difficult.

“It’s another government, and one that doesn’t cooperate much with the United States," Tobias said. “The question is how to find assets that are probably in the United States that the parents could secure.”

Contributing: Sean Rossman