Female North Korean workers employed at some North Korean restaurants in Beijing have returned home en masse since late last month, Kyodo News reported Wednesday, citing the possibility that China might have tightened visa controls. Since the departure of North Korean female employees beginning late November, North Korean restaurants in the Chinese capital have been scrambling to stay afloat by hiring Chinese staff or suspending the serving of North Korean cuisine, Kyodo said. The news agency, citing diplomatic sources, speculated that the incident may have been related to visa requirements in China, although it said details remain unknown. "There is information suggesting that employees at North Korean restaurants in China have made use of student or training visas. It is also possible that Chinese authorities have tightened visa controls," Kyodo said. The news agency pointed out that the U.N. Security Council in 2017 demanded that member states forcibly repatriate overseas North Korean workers in compliance with sanctions against the country.