WASHINGTON — In an apparent swipe at President Donald Trump, Sen. Rob Portman said the United States cannot “be naïve” in its dealings with North Korean leader Kim Jong Un and the “brutal nature of a regime” whose mistreatment of Otto Warmbier led to his death in 2017.

Speaking on the Senate floor after Trump said earlier Thursday in Hanoi he did not believe the “top leadership” in North Korea knew of Warmbier being badly treated in prison, the Ohio Republican said Warmbier’s “detainment and his sentence were appalling; unacceptable by any standards.”

“We can’t be naïve about what they did to Otto, about the brutal nature of the regime that would do this to an American citizen,” said Portman.

Warmbier, who was from the Cincinnati suburb of Wyoming and attended the University of Virginia, was seized by North Korean officials during a trip to the reclusive country. While in prison, Warmbier suffered a severe brain injury and he died in a Cincinnati hospital just days after Pyongyang released him.

>>Video: Portman: “We can't be naive about what they did to Otto”

At a news conference in Hanoi, Trump said Kim told him during a summit that “he felt badly” about Warmbier’s death from "bad things" in prison. But Kim “tells me that he didn’t know about it and I will take him at his word,” Trump said.

“I know the Warmbier family very well,” said the president, who had them as his guests at this year's State of the Union speech. “I think they're an incredible family. What happened is horrible. I really believe something very bad happened to him."

But Portman, who favors talks with Pyongyang on reducing its arsenal of nuclear weapons, cast doubt on Kim's claim.

“Who did the North Korean government tell about the fact that he had this brain damage? Portman asked. “No one. Unbelievable.”

Other Ohio lawmakers were even blunter in their criticisms.

“Warmbier’s life was taken by the abusive and oppressive regime in North Korea,” Dayton Republican Rep. Mike Turner said. “As the head of that regime, Kim Jong-Un bears full responsibility for Otto’s death.”

Sen. Sherrod Brown, D-Ohio, said “North Korea murdered” Warmbier and Trump “has a responsibility to make sure they face the consequences. Anything short of that is unacceptable.”

The Ohio Democrat added, “The president of the United States is sending a message to dictators around the world that he believes autocrats when they lie or when they cover up, or when they justify policies that result in the deaths of human beings.”

Rep. Steve Stivers, R-Upper Arlington, said it is “hard for me to believe that Kim Jong-un had no knowledge of Otto Warmbier's treatment. Regardless of whether he was aware or not, he is ultimately responsible.”

“Any leader who allows gulags to operate in their country and allows thousands to die as a result is responsible for each and every one of those deaths,” Stivers said.

A spokesman for Ohio Gov. Mike DeWine said the Republican "respectfully declines comment."

A federal judge has ordered North Korea to pay more than $500 million in a wrongful death suit by Warmbier's parents.

Former U.N. Ambassador Nikki Haley also seemed to distance herself from Trump, tweeting: "Americans know the cruelty that was placed on Otto Warmbier by the North Korean regime."

Rep. Adam Schiff, D-California, questioned in a tweet Trump "accepting Kim’s denial of involvement in Warmbier’s death? Detestable, and hearkens back to Trump’s duplicitous acceptances of denials from other dictators."

Trump has also given credibility to denials by Russian President Vladimir Putin and Saudi Crown Prince Mohammed bin Salman of misdeeds despite information from U.S. intelligence agencies.

In July 2018, Trump said in a joint news conference with the Russian leader that Putin “was extremely strong and powerful in his denial” and thus Trump didn't “see any reason” to believe he was involved in attempts to manipulate American elections. Later, Trump backed off that remark somewhat.

Trump also expressed belief in bin Salman's denial — again despite U.S. intelligence findings — that the Saudi government was not involved in last fall's killing of Washington Post journalist Jamal Khashoggi.

jtorry@dispatch.com

@jacktorry1