SEOUL, July 30 (UPI) -- Five North Korean flights flew to Vladivostok on Monday, a trip unusually involving cargo planes, according to NK News.
Three cargo planes and two passenger flights of the North Korean national carrier Air Koryo traveled to Russia's far-eastern port city on Monday, according to a spokesperson of Vladivostok International Airport, the report said.
The trip involves three unusual cargo flights of the model used to transport personal armored vehicles of North Korean leader Kim Jong Un in his overseas trips, including his visit to China in June.
The report said the IL-76 cargo aircraft has never made a trip to Vladivostok since 2010. The report didn't specify what the aircraft was transporting between Pyongyang and Vladivostok.
Two passenger flights make regular round-trips between Pyongyang and Vladivostok on Monday and Friday. And extra passenger flights were spotted flying during weekdays by NK News.
The report cited an anonymous source saying the extra cargo flights were sent to bring back North Korean workers in the Russian city as their work permit expires soon.
According to the U.N. Resolution 2397, North Korean overseas workers should return to the home country before December 2019. The resolution includes revenues generated from North Korean workers overseas in sanctioned items. It also states that the workers should return no later than 24 months from the adoption of the resolution in December 2017.