A coordinated campaign by fundamentalist Islamic groups has led to Facebook shutting down a number of Arabic atheist pages, according to The News Hub.

The site reported that the social media platform has removed more than 16 Arabic-speaking atheist pages due to "violations" of its 'Community Standards'. The closure has left more than 100,000 atheists in Muslim dominant countries without a platform to share with other non-religious people.

A campaign under the tag #FacebookVSFreeSpeech has been launched to challenge Facebook chief Mark Zuckerberg by Atheist Alliance – Middle East and North Africa (AA-MENA).

The social media platform does not usually police reports of violations of Community Standards as they will vary around the world. Instead the site makes an automatic decision based on the number of complaints. If a post or groups gets enough reports of violations, Facebook will shut down the content and delete it.

This leaves vulnerable groups open to being targeted by so-called "cyber jihadists" who urge their large following to flood Facebook with complaints.

It is part of a wider online campaign in the Middle East and North Africa (MENA) to quell expressions of atheism or anything other than the socially conservative Islamic norm. But the abuse is not just online.

Yemeni activist Omar Bataweel was shot outside his home on April 22, according to The News Hub. The outspoken critic of Islam had shared his views on Facebook, which led him to receive death threats prior to his killing. His case remains open.

The AA-MENA campaign has tracked the tracked the progress of Arabic-speaking atheist groups and pages and frequently criticises Facebook's approach to freedom of speech.

The group has three goals for its campaign; reactivate the pages, convince Facebook to respect the rights of irreligious people in the MENA region and; convince Facebook to reform its procedures so a just evaluation is made of any alleged violation of Community Standards.

Maryam Namazie, spokeswoman for the Council of Ex-Muslims of Britain, tweeted she had been blocked by Facebook after she shared an ex-Muslim's page that depicted Zuckerberg as an ally of ISIS.

There remains a severe punishment for renouncing Islam in many Middle Eastern countries. Even if it allowed legally, ex-Muslims often face severe persecution and harassment from family and locals.