31 CFR §510.518

1. (a)Vessels and aircraft in which a foreign person has an interest that have called or landed at a port or place in North Korea within the previous 180 days, and vessels in which a foreign person has an interest that have engaged in a ship-to-ship transfer with such a vessel within the previous 180 days, are authorized to call or land at a port or place in the United States in the following circumstances only:
   1. (1)The vessel is in distress and seeks refuge in the United States;
   2. (2)The vessel's call at a port in North Korea was due solely to its distress and the resulting need to seek refuge;
   3. (3)The aircraft is engaging in a nontraffic stop or an emergency landing in the United States; or
   4. (4)The aircraft's landing in North Korea was due solely to an emergency landing.
2. (b)For purposes of this section, a nontraffic stop includes a stop for any purpose other than taking on or discharging cargo, passengers, or mail.