MOSCOW (AP) — The founder of a Russian encrypted messaging app is defying the government’s request to provide information about his company.

The head of the Russian communications regulator on Friday in an open letter to Telegram founder Pavel Durov threatened to block Telegram unless Durov hands over details about the app. The move would require Telegram, which prides itself on privacy, to keep and share users’ chat histories and encryption keys with the government.

Durov said in a post on his social media page Friday that the threat to block Telegram was “sabotage of state interests.”

He says that if Telegram is banned in Russia, the private chats that Russian officials and their friends currently conduct via his messaging app will be conducted through apps that store their data abroad.