DUSHANBE -- RFE/RL's Tajik- and Russian-language websites, YouTube, and a number of Russian social networks were inaccessible in Tajikistan on May 28.
Customers of the Internet providers Vavilon, Indigo, TajikTeleCom, and Megafon across the country complained that they were not able to connect to the websites.
Asomuddin Atoev, the chairman of Tajikistan's Association of Internet Service Providers, told RFE/RL that access to the sites was being blocked by some Internet service providers based on an oral order from the State Communications Service.
Atoev said reports about a top Tajik police commander who joined the Islamic State (IS) extremist group were behind the order.
"That is not the way to solve the problem, that is violating the Internet users' right to receive information," he added.
Officials at the state Communications Service said they have nothing to do with the Internet blockage.
In a video posted on YouTube on May 27, Colonel Gulmurod Halimov, the commander of the Tajik Interior Ministry's special forces, said he had joined the IS group in protest at official restrictions on religious observance in Tajikistan.