Facebook's free internet initiative, Free Basics, has been suspended in Egypt just two months after launching.
The service, which is part of the firm’s wider Internet.org plan, gives people in developing countries access to some basic internet services, including Facebook itself.
It is unclear at this time why the service has been stopped but Free Basics has been criticised by net neutrality advocates who say that companies should treat all internet traffic equally.
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Egypt's mobile network Etisalat began offering Free Basiscs to its customers two months ago and Facebook says that three million Egyptians had since signed up.
But the service was shut down on December 30 for reasons which remain unclear, although the social network did play a large role in organising the Arab Spring which ousted former President Hosni Mubarak.
The fifth anniversary of the Arab Spring is less than a month away.
This isn't the first setback that Free Basics has run into. Last month the Telecom Regulatory Authority of India informed Facebook’s network partner in the region, Reliance Communications, it should withdraw support.
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The US firm's Internet.org initiative aims to provide web access to billions of people around the world.
Users can use the Free Basics app and website to visit websites including Facebook and BBC News, without incurring data charges.
The service has courted controversy as it raises the issue of carriers charging to access one website and not others.
Facebook CEO Mark Zuckerberg wrote an op-ed in the Times of India in which he defended Free Basics: "In every society, there are certain basic services that are so important for people’s wellbeing that we expect everyone to be able to access them freely.
"In the 21st century, everyone also deserves access to the tools and information that can help them to achieve all those other public services, and all their fundamental social and economic rights.
"That’s why everyone also deserves access to free basic internet services."