Police in Cairo have detained a blogger whose posts have been critical of the Egyptian government.
Ayyoub's blog has posted criticism of the 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.
In recent weeks, bloggers have been exposing what they say was the sexual harassment of women at night in downtown Cairo in full view of police who did not intervene.
Bloggers are at the centre of Egyptian political activism
Mr Siyam's host on Saturday night, Muhammad Sharqawi, was detained for several weeks earlier this year.
The most recently detained blogger, Abdel Kareem Nabil, was detained in Alexandria on 6 November and was charged with disrupting public order, inciting religious hatred and defaming the president.
Amnesty International says Mr Amer appeared to have been detained for expressing critical views about Islam and Egypt's al-Azhar religious authorities.