North Korea sentenced a U.S. man Sunday to six years in labor camp for illegally entering the country and committing espionage.

The Supreme Court of North Korea said that 24-year-old Matthew Miller, a native of Bakersfield, Calif., tore his tourist visa at Pyongyang's airport on arrival on April 10 this year and wanted to  "experience prison life so that he could investigate the human rights situation."

Miller is the second U.S. citizen to serve a hard prison sentence in North Korea. The U.S. says the country is using them to gain political concessions, reports Bangkok Post, citing an Agence France-Presse report.

"He committed acts hostile to the (North) while entering the territory of the (North) under the guise of a tourist last April," the state-run Korea Central News Agency said in a statement.

The prosecution argued that Miller's claim of seeking asylum was a trick and he also falsely claimed to have secret information about the U.S. military in South Korea on his iPad and iPod. Miller's trial lasted approximately 90 minutes, and he was handcuffed and taken out of the courtroom following the verdict. The court also ordered that no appeal on the decision will be entertained. Miller had waived the right to a lawyer, reports the Associated Press.

It remains unclear which labor camp Miller will be sent to.

Another U.S. citizen already serving a 15-year sentence in a labor camp is 46-year-old Kenneth Bae. He was allowed an interview with CNN earlier this month in which he described his deteriorating health.

"I have been going back and forth from hospital to the labor camp for the last year and a half," he said, adding that he was working eight hours a day for six days a week at the camp.

The state found Bae guilty of trying to evangelize inside North Korea. He said that he was diabetic and suffered from backaches and high blood pressure. The United States appealed to North Korea to release Bae on humanitarian grounds.

The Daily Telegraph reports Jeffrey Fowle, a 56-year-old American who was arrested in North Korea in May for leaving a Bible with his contact details written inside under a bin in the lavatory of a restaurant, is expected to go on trial shortly.