DUBAI: The CEO and founder of the messaging application Telegram says that the service has been blocked in Iran after his company refused to allow authorities to spy on users.

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 Thursday.

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.

Iran blocks social media websites like Facebook and Twitter and censors others, though top officials have unfettered access to social media.