Iran's judiciary has blocked newly introduced call features on a highly popular messaging app called Telegram.
It was not immediately clear whether the reason for the blocking of voice calls, introduced last week, was a political move ahead of the country's May presidential election or an attempt to protect the commercial interests of Iranian telecom companies.
Telegram CEO Pavel Durov confirmed the restrictions in a message posted on his official channel.
"In Iran, where Telegram has some 40 million active users, Telegram voice calls have been completely blocked by the country's Internet providers and mobile operators following an order from the judiciary," Durov wrote.
The block follows March arrests in Iran of 12 managers of popular reformist and pro-government Telegram channels -- a move that some critics say was part of crackdown ahead of the May presidential election.
Iran's judiciary said the 12 telegram managers were arrested on national security charges.
But the arrests also have been criticized by Iran's President Hassan Rohani, who is seeking a second term.
Many Iranians use Telegram for messaging purposes but also to access and exchange news and information.
Iranian media outlets and many of the country's politicians maintain their own channels on the Telegram app.
Based on reporting by AFP and Bloomberg