N. Korea Tells ABC News: 'No Exception' to US Detainees Being Subject to Wartime Laws

The warning comes on the heels of a reported missile test Tuesday.

— -- U.S. citizens being held in North Korean prisons will be subjected to wartime laws with "no exception," a Pyongyang diplomat told ABC News in an exclusive interview.

The declaration comes on the heels of a report by South Korea's Yonhap News Agency that claimed North Korea launched a ballistic missile into Japan's exclusive economic zone for the first time today, an incident that has raised tensions in the region.

It is unclear what the wartime designation would mean for Warmbier or Kim.

Ruth Wedgwood, a lawyer and university professor at the Johns Hopkins University School of Advanced International Studies, told ABC News that “it’s hard to know what North Korea means” by the statement.

“Even under wartime laws, they can’t torture or execute prisoners,” Wedgwood said, citing the Geneva Convention.

Warmbier was sentenced in March to 15 years of hard labor, after an hour-long trial

"I was used and manipulated," he said during the trial, weeping. "Please save my life."

Richardson called the 15-year sentence "crazy" in an interview with ABC News in March.

Kim Dong Chul, a South Korea-born businessman and naturalized U.S. citizen, had been living in China with his wife at the time of his arrest in North Korea on charges of espionage. He was sentenced to 10 years in prison with hard labor after a brief trial in Pyongyang in April.

When Kim was paraded before the media in Pyongyang, he said he had collaborated with and spied for South Korean intelligence authorities in a plot to bring down the country's leadership and spread religion to North Korean people, according to The Associated Press.