The White House has demanded the immediate release of US student Otto Warmbier, 21, and imposed harsh new sanctions on his captor, North Korea.
The university student was sentenced on Wednesday by the North Korean Supreme Court to 15 years in prison with hard labour for theft of a propaganda poster.
Mr Warmbier said he was visiting the country on holiday and took the banner at the request of the mother of a friend, who he said offered a used car worth US$10,000 in exchange for the trophy.
The student has become a pawn in the escalating diplomatic feud between the dictatorship and the US. North Korea recently claimed to have developed and tested long-range nuclear weapons. Experts doubt the validity of the claim, but the US is concerned.
In the Warmbier case, North Korean officials said the student committed an anti-state crime with “the tacit connivance of the US government and under its manipulation”.
In the hours after the sentence was handed down, the White House announced “robust new sanctions” on the North.
“These actions are consistent with our longstanding commitment to apply sustained pressure on the North Korean regime,” White House spokesman Josh Earnest said in a statement on Thursday.
“The US and the global community will not tolerate North Korea’s illicit nuclear and ballistic missile activities, and we will continue to impose costs on North Korea until it comes into compliance with its international obligations.”
The statement did not reference Mr Warmbier directly, and are aimed at stopping North Korea’s nuclear and ballistic missile programs by limiting its exports and inspecting all cargo coming in and out of the country. But the White House has called on the dictatorship to release the student.
US tourism to North Korea is legal, but the State Department strongly advises against it.