Trump sparked widespread criticism when he told reporters at this week's summit with Kim in Vietnam that he believed the North Korean leader's claim that he didn't know what happened to Otto Warmbier during his detention.

The 22-year-old Warmbier died days after being sent back to the United States from North Korea in a coma in 2017.

"Of course I hold North Korea responsible for Otto's mistreatment and death," Trump wrote on Twitter after Warmbier's parents had weighed in on the controversy.

"Most important, Otto Warmbier will not have died in vain. Otto and his family have become a tremendous symbol of strong passion and strength, which will last for many years into the future."

After Fred and Cindy Warmbier issued a statement earlier in the day saying that "Kim and his evil regime are responsible for the death of our son," Trump said that his comments had been "misinterpreted."

"I never like being misinterpreted, but especially when it comes to Otto Warmbier and his great family," he said.

"Remember, I got Otto out along with three others. The previous Administration did nothing, and he was taken on their watch," said the president.

"I love Otto and think of him often!", he added in his tweets, which made no mention of Kim.