Egyptian police arrested 30 members of the outlawed Muslim Brotherhood on Sunday, police said.
A police official, who spoke on condition of anonymity because he was not authorized to speak to the media, said most of the detainees were students of Helwan University who were arrested for alleged illegal activities.
The Muslim Brotherhood's Web site said many of the detainees were Brotherhood candidates running in student elections at the university, which is located on the outskirts of Cairo.
"A huge police force surrounded and stormed the houses of the students in the early hours of the day and turned the area into a battleground," said the group on its Web site.
The police official said books and pamphlets propagating the Brotherhood's ideas were confiscated from inside the students' homes.