Egypt's military leaders, who took control of the country after Mubarak's ouster, were keeping a wary eye on the developments, according to a statement released by the Egyptian armed forces and read on state-media.

"The armed forces are watching with sadness and worries the current developments in the country, with its consequences and how it led to divisions," the statement said, according to state media.

"We stress that dialogue is the ideal and only solution to reach an agreement that realizes the interests of the nation and its citizens. Anything other than that will lead us into a dark tunnel with catastrophic consequences, which we will never allow to happen."

Adel Saeed, a spokesman for Egypt's newly appointed general prosecutor, said Friday morning that opposition figures Hamdeen Sabahy, Mohamed El Baradei and Amr Moussa are being investigated for allegedly "conspiring to topple" the government.

All three are well-known internationally; ElBaradei being a Nobel Peace Prize laureate. Moussa a onetime head of the Arab League, and Sabahy is an Egyptian political figure. They are now being probed for their role in the opposition against Morsy.

ElBaradei said on Twitter: "I call upon all the national forces and figures not to participate in a dialogue that lacks all the basics of a truthful discourse. We support a dialogue that is not based on the policy of arm-twisting and forcing the status quo."

Those taking part in the protests around the North African nation say the scenes are similar to those of the 2011 uprising that led to Mubarak's ouster. This time, they say, dissent is being vigorously stamped out by Morsy's backers in government and on the street.

Specifically, they spoke of thugs with knives and rocks chasing activists, presidential backers belittling opponents and pressure from various quarters to go home and be quiet.

"It's exactly the same battle," said Hasan Amin, a CNN iReporter.