The United States government has urged Americans in North Korea to get out before a travel ban goes into effect on September 1.
Officials said that anyone currently in North Korea that hold a U.S. passport should leave before the restrictions take place next month, the U.S. State Department said in a statement.
The ban, first reported in July, comes after the death of U.S. tourist Otto Warmbier, who suffered brain damage while under arrest in North Korea.
"The Department of State has determined that the serious risk to United States nationals of arrest and long-term detention represents imminent danger to the physical safety of United States nationals traveling to and within the Democratic People's Republic of Korea (DPRK)," the notice said.
At least 16 U.S. citizens have been detained in North Korea in the past 10 years, the State Department said.
Journalists and humanitarian workers may apply for exceptions to the ban, according to the public notice.
(With inputs from Reuters)