Meanwhile, security forces sealed off the square with armored vehicles and barbed wire after hundreds of anti-military protesters rallied near it, just days before the third anniversary of Egypt's January 25, 2011, uprising.
Groups across the political spectrum have called for competing rallies Saturday, some calling for a new revolution and others calling for the country's military chief to become president.
Egyptian activists say they are now regularly prosecuted, painted by the media as traitors, and subjected to intimidation, a stark contrast to post-Mubarak days when activists were hailed as national heroes.
The country has experienced regular bouts of political violence since the 2011 ouster of longtime autocratic leader Hosni Mubarak, but the violence escalated after June 30, when millions took to the streets demanding their first elected President Mohammed Morsi step down.
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Hundreds were killed in by an ensuing state crackdown and thousands arrested.
El-Sissi's supporters say they plan to use the Jan. 25 date to call for him to run for president, saying he is the only leader strong enough to stem the unrest.
Morsi's group meanwhile said yesterday that they wanted secular-leaning groups to rally together with them to bring down the post-coup political order, a demand those secular-leaning groups immediately shot down.