MTN Cameroon reported on its last week that it had suspended its Twitter via SMS service. "We can't comment further than 'security reasons' on #Government instructions," according to a message on the of Georges Mpoudi Ngole, MTN Cameroon's CIO.

The government has not issued an official statement on the matter.

Twitter via SMS lets users send messages at the cost of a local text message. The service allows users without access the Internet to update their status messages. Twitter service via Web-connected PCs in Cameroon remains uninterrupted.

Social media has played a major role in uprisings in North Africa, including the popular movement in Egypt that unseated President Hosni Mubarak. The phenomenon is said to worry other African leaders.

"Over the years, Cameroonians abroad have used social media to organize anti-government rallies in Europe and the United States that have embarrassed and infuriated the regime," said Dibussi Tande, a, via e-mail.