Egyptian officials say members of the Muslim Brotherhood - including a deputy leader of the group, Mohammed Khayrat al-Shater, are to stand trial before a military court.
The Brotherhood members have been detained since December when members wore militia-style uniforms during a demonstration at al-Azhar University in Cairo.
Egyptian authorities accuse the movement of seeking to revive its military wing.
The government has also frozen the assets of many Brotherhood members while it investigates charges of money laundering.
The Muslim Brotherhood is officially banned in Egypt but its members - running as independent candidates - represent the largest opposition bloc in Egypt's parliament.
President Hosni Mubarak has proposed reforms that would, if adopted, formally ban all religious groups from forming political parties.
Some information for this report was provided by AFP, AP and Reuters.