Police in Cairo have detained a blogger whose posts have been critical of the Egyptian government.
Rami Siyam, who blogs under the name of Ayyoub, was detained along with three friends after leaving the house of a fellow blogger late at night.
No reasons have been given for Mr Siyam's detention. The other friends were released after being questioned.
Human rights groups have accused Egypt of eroding freedom of speech by arresting several bloggers recently.
BBC Arab Affairs analyst Magdi Abdelhadi says blogging in Egypt is closely associated with political activism in a culture where democratic freedoms are severely restricted.
As an Egyptian, I abhor the restrictions on political freedoms in the country, and, even more so, the brutal measures adopted by Hosni Mubarak's regime to prevent political dissent.
Actually, my father was a victim of these measures - during the 1950s, as a young geology student and journalist, he was imprisoned and tortured for his criticisms of Gamal Abd-el Nasser's government, and for being a member of an illegal Communist party. My father's political asylum is therefore one of the reasons that I am a British national.