In a message on Twitter late Wednesday, Pavel Durov wrote that Iranian officials demanded the company provide them with "spying and censorship tools." He said: "We ignored the demand, they blocked us."
Durov added that the company was trying to find a way to restore service to its Iranian users. Some users in Tehran said it worked today.
Iran's official IRNA news agency on Wednesday quoted Mahmoud Vaezi, the country's communications and information technology minister, denying that authorities were "filtering" Telegram.