Mahmoud Ezzat, the deputy leader of the Muslim Brotherhood, and two senior officials in the organization were detained Monday morning. Security officials said they were participating in banned political activity.
Members of the Muslim Brotherhood won 20 percent of the seats in 2005 parliamentary elections running as independent candidates because they are banned from politics.
The organization claims the arrests are part of a broader crackdown against opposition parties ahead of parliamentary elections scheduled for November.
The Brotherhood was founded in 1928, becoming one of the founding organizations advocating militant Islam. It renounced violence, however, in the 1970s, though a splinter group later went on to join al-Qaida.
Muslim Brotherhood leader Gamal Nassar told al-Jazeera the arrests were part of a broader message from the ruling party in Cairo.
"The Egyptian regime must review such practice because the Muslim Brotherhood has a presence on the streets of Egypt, it gains legitimacy from the people and has 86 seats in the Parliament," he said.
Cairo is under pressure to introduce democracy as Hosni Mubarak has reigned as president since 1981.
Security forces arrested 20 members of the Muslim Brotherhood during the weekend.
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