Ahmed Mahmoud Abdallah, also known as 'Abu-Islam', is editor of the Balady Net news site and former editor of the now defunct opposition newspaper Al-Shaab. He is a member of the Union of Egyptian Journalists and head of the Centre for Islamic Enlightenment, a project that aims to encourage different religions to work together.
Mr Abdallah was arrested in Cairo on 5 December by state security agents.
"Website journalists and bloggers should enjoy the same legal protection and respect as journalists working for traditional media," said a spokesperson for press freedom group Reporters Sans Frontières.
"The decision to arrest a journalist or blogger is serious and should only be taken in the course of transparent judicial proceedings."
In October, 21-year-old law student and blogger Abdolkarim Nabil Seliman was detained for three weeks for criticism of the government and Islam. He campaigns against violence and discrimination towards Muslim and Arab women.
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