TOKYO — Fred Warmbier clearly struck a nerve in North Korea when he traveled to South Korea last week to remind the world, amid an Olympic-inspired detente, of the horrors of the Kim regime.

The regime has again insisted that Otto Warmbier — the University of Virginia student who was detained in North Korea for 17 months, most of it in a coma, and died shortly afterward — was nothing but a “criminal.”

“The United States is again kicking up a defamation campaign against the DPRK, intentionally attributing Warmbier’s death to the latter,” an official in the North Korean Foreign Ministry’s Institute for American Studies was quoted as saying Friday, using the abbreviation for the state's official name.

Fred and Cindy Warmbier, Otto’s parents, were guests of first lady Melania Trump during the State of the Union address, when President Trump called them “powerful witnesses to a menace that threatens our world.”

Then Vice President Pence invited Fred Warmbier to accompany him in South Korea, where he was attending the opening of the Winter Olympics.

“I’m telling the truth about the regime’s treatment of my son. But guess what, they do this to countless other people,” Warmbier said in an interview with NBC News on the sidelines of the PyeongChang Winter Olympics. “This isn't defiance. This is telling the truth. This is standing up and being the voice of Otto.”

North Korea launched a charm offensive related to the Olympics, sending 22 athletes to the Games but also dispatching hundreds of cheerleaders and musicians, as well as a high-level delegation that included leader Kim Jong Un’s sister.

Kim Yo Jong delivered an invitation from her brother to the South Korean president, asking him to go to Pyongyang for talks. This outreach, after a year of missiles and threats, dominated the headlines at the opening of the Games.

North Korea clearly did not appreciate Warmbier’s efforts, or the broader efforts by the Trump administration, to remind the world of its rampant human rights abuses just as it was trying to paper over them.

The Trump administration was “kicking up a fuss” about North Korea and trying to “tarnish” its international image by talking about Otto Warmbier’s death, the unnamed official said in the statement, published by the North’s Korean Central News Agency Friday.

“It is not accidental that there is an assessment coming from the U.S. that the present administration’s increased move of taking up the DPRK's ‘human rights’ issue amounts to an attempt for ‘regime change,’” the statement said.

The Trump administration has been invoking North Korean’s human rights abuses at home and its desire to hurt people in the outside world, rhetoric that some have compared with the Bush administration's arguments in the run-up to the Iraq War.

At the end of 2015, Otto Warmbier, then 21, was a University of Virginia student heading to a study abroad program in Hong Kong. On the way, he joined a five-day New Year’s tour to North Korea, aimed at young adventure seekers.

But in the early hours of New Year’s Day, he apparently went to a staff-only floor in his Pyongyang hotel and took down a poster lauding the Kim regime. North Korea later released grainy footage showing an unidentifiable man taking the long board from the wall and propping it down on the floor.

Warmbier was detained at the airport the following day as he went to depart Pyongyang, and later charged with “perpetrating a hostile act” against North Korea. He issued a tearful, pleading apology on camera.

After a trial lasting only an hour and at which he had no representation, he was sentenced to 15 years hard labor.

What happened next is unclear. North Korea says Warmbier suffered food poisoning then had an allergic reaction to the medicine he was given in detention.

What is known, however, is that he fell into a coma and the North Korean authorities kept this secret for some 15 months. It was only after diplomatic negotiations related to his release, and that of three other Americans still being held, that officials in Pyongyang divulged his condition.

He was medically evacuated home, to the University of Cincinnati Medical Center, but was discovered to have severe brain damage. He died six days later.

His parents have said that he was tortured during his captivity but declined an autopsy. The physicians who treated him in Cincinnati said they found no evidence of botulism or of torture.

North Korea has made something of a habit of detaining Americans for political purposes in recent years, but the others have all eventually been released in relatively healthy condition.

North Korea repeated its claim that the U.S. should explain “why Warmbier suddenly died less than one week after his return to U.S. in normal physical condition.”

Warmbier was in a coma when the American evacuation crew, which included two doctors, arrived in Pyongyang last June to collect him.

The North Korean official also asked Friday why the U.S. had not made a big deal about Evan Hunziker, an American who died a month after being released from detention in North Korea in 1996.

Hunziker, whose mother was from South Korea, was a troubled man with a history of alcohol and drug abuse, and who had spent time in jail. On a dare, he swam across the river from China to North Korea one night in 1996, and was promptly arrested.

A month being released, Hunziker killed himself.

As it has come under increasing scrutiny for its human rights abuses, North Korea has fired back by accusing the United States of violations. The latest statement was no exception.

“The U.S. would be well advised to mind its own miserable human rights record full of all social disturbances and bloody tragic events caused by Trump’s unbridled remarks of advocating for white supremacy and racism, which are subject to international curse and denunciation,” the statement’s official English translation said.