Indonesia is blocking web versions of the encrypted Telegram instant messaging app and will ban the app completely if it continues to be a forum for propaganda and calls for violence, officials said.

In a statement on Friday evening, the Ministry of Communications and Information Technology said it has asked internet companies to block access to 11 addresses that the web version is available through.

"This has to be done because there are many channels on this service that are full of radical and terrorist propaganda, hatred, ways to make bombs, how to carry out attacks, disturbing images, which are all in conflict with Indonesian law," the ministry said in a statement on its website.

Samuel Pangerapan, the director general of informatics applications at the ministry, said they are preparing for the complete closure of Telegram in Indonesia if it does not develop procedures to block unlawful content.

READ MORE: Indonesia signs decree to ban 'extremist' groups

The move comes amid heightened concerns over the growing presence and influence of Islamic State of Iraq and Levant (ISIL, also known as ISIS) in Southeast Asia.

Indonesia, the world's most populous Muslim nation, has seen a resurgence in attacks, inspired in large part by ISIL; a twin suicide bombing at a Jakarta bus station in May killed three police officers and wounded several others.

Public outcry

The partial block has sparked public outcry in Indonesia, with Twitter and Facebook exploding with negative comments and some people reporting they were unable to access the web.telegram.org domain.

Indonesians are among of the world's biggest users of social media.

Sorry @durov, Telegram got blocked in Indonesia because of security reasons.

I know, it's like blocking the Tor browser "because terrorists" — Nathan Ardany Tanara (@TweetNAT45) July 14, 2017

Telegram did not immediately respond to a request for comment.

Founded in 2013 by Russian brothers Nikolai and Pavel Durov, the application is a free messaging service that can be used as a smartphone app and on computers through a web interface or desktop messenger.

Pavel Durov, Telegram's founder, in a tweet on Friday called the block "strange".

"[W]e have never received any requests/complaints from the Indonesian government," he said.

Suspected fighters arrested by Indonesian police recently have told authorities that they have communicated with fellow members of their group via Telegram and received orders and directions to carry out attacks through the app, including from Bahrun Naim, an Indonesian with the ISIL group in Syria accused of orchestrating several attacks in the past 18 months.

Its strong encryption has contributed to its popularity with those concerned about privacy and secure communications in the digital era but also made it useful to armed groups and other criminal groups.