Russia has threatened to block access to the Telegram messaging platform unless the company that runs the app provides more information about itself (via Sky News).

The head of communications regulator Roskomnadzor, Alexander Zharov, said repeated efforts to obtain the information had been ignored by the company and warned that "time is running out" for the app.

"There is one demand and it is simple: to fill in a form with information on the company that controls Telegram," Zharov said in an open letter. "And to officially send it to Roskomnadzor to include this data in the registry of organizers of dissemination of information. In case of refusal… Telegram shall be blocked in Russia until we receive the needed information."

Telegram's non-response appears to be down to the repercussions of handing over the requested details: Doing so would effectively add it to the state regulators' registry, which would require it to retain users' chat histories and encryption keys and share them with authorities if asked, according to Russian news agency TASS.

The demand isn't the first time the Russian founders of Telegram – Kremlin, Nikolai and Pavel Durov – have failed to comply with state requests. In 2014, the Durovs refused to turn over data on Ukranian users of Vkontakte, a social network they also set up together.

Telegram claims to split its encryption keys into separate data centers around the world to ensure "no single government or block of like-minded countries can intrude on people's privacy and freedom of expression".

According to the group's policy, it can only be forced to hand over data if "an issue is grave and universal enough to pass the scrutiny of several different legal systems around the world".