The advisory comes two days after Pyongyang confirmed it has detained a fourth U.S. citizen.
Kim Hak-song, an employee of Pyongyang University of Science and Technology, was charged with engaging in “hostile acts” against the Kim Jong Un regime.
The State Department warning included an extensive list of activities that could lead to arrest in the relatively isolated country.
Acts that are not considered criminal in other countries, including bringing pornography, exchanging currency with an unauthorized vendor, or having unauthorized interaction with locals could lead to arrest, according to the State Department.
One of the American detainees, Otto Warmbier, was detained for removing a North Korean political banner. He was sentenced to 15 years of hard labor in March 2016.
The U.S. advisory also pointed out traveling with a member of a tour group or using a tour guide “will not prevent North Korean authorities from detaining or arresting you.”
“Efforts by private tour operators to prevent or resolve past detentions of U.S. citizens in [North Korea] have not been successful,” the statement read.
Both Warmbier and Kim Sang Duk, also known as Tony Kim, were detained as they were preparing to board their flight at the international airport in Pyongyang.
Tony Kim was also an employee of PUST.