North Korean authorities have reportedly blocked access to Facebook and Twitter for the few people in the country with open Internet access.
The move came into effect earlier this week, according to a report by the Russian ITAR-TASS news agency, which is one of the few foreign news services to maintain a bureau in the country.
Most North Koreans don't have access to a computer, and those who do are restricted to a nationwide intranet. Available through universities, libraries and other state-run establishments, the intranet has websites that include government propaganda, information about science, technology and culture, and even cooking recipes.
Access to outside information is tightly curtailed by the government, which jams foreign radio broadcasts and restricts international phone calls and texts. North Korea is consistently ranked among the worst counties for press freedoms and human rights.
The handful of foreign residents who live there, many of them aid workers and business people, are permitted to access the Internet through fixed and wireless connections, but even over those links, access to Facebook and Twitter has been cut, ITAR-TASS reported.
The report couldn't immediately be verified, and neither Facebook nor Twitter responded to requests for comment.
In September, North Korea's State Radio Regulatory Department told foreign embassies and aid organizations they could not use Wi-Fi or satellite Internet connections without government approval. The ruling, a copy of which was obtained by specialist news site NK News, hinted that an earlier report that embassies were deliberately running open Wi-Fi networks to provide public Internet was correct.
The ruling said, "the signals of regional wireless network, installed and being used without licence, produce some effect upon our surroundings."
Organizations wishing to continue using Wi-Fi were instructed to consult with the government so their services could be checked. Those that didn't were threatened with an $11,000 fine.
Martyn Williams covers mobile telecoms, Silicon Valley and general technology breaking news for The IDG News Service. Follow Martyn on Twitter at @martyn_williams. Martyn's e-mail address is email@example.com