Despite army general Abdel Fattah El Sisi's statement, tens of thousands of pro-Morsi protesters filled Nasr City on Thursday to demand the deposed president's reinstatement, continuing a now weeks-long vigil following his removal by the army.

Sisi also vowed to stick to a political roadmap that laid the way for a reform of the constitution and new elections within some six months.

He said his appeal for protests was not a call for violence and expressed support for efforts for national reconciliation.

The military reacted soon after, declaring a "state of alert".

Ahmed Al-Meslemani, media adviser to the interim president Adly Mansour, later echoed the call, asking people to take to the streets to protect the "revolutionary legitimacy" and support efforts to "fight terrorism".

The Muslim Brotherhood also reacted quickly, with senior member Essam al-Erian issuing a statement directed at Sisi saying: "Your threat will not prevent millions to rally against [the] coup ... You have been always in your office conspiring."

In a press conference later, Egypt's opposition Islamist coalition read out a list of its stipulations. They said Sisi should be tried by for crimes against humanity, for calling for Friday's rally, which they said was "an announcement of civil war".

They also called on their supporters to oppose Sisi's call.

"[General Abdel Fattah] al-Sisi's threats are an announcement of civil war," said the Muslim Brotherhood-led coalition which has been demanding president Morsi's reinstatement ever since his overthrow in a July 3 coup.

In a speech on Wednesday to army graduates, El Sisi called for pro-army protests to be held on Friday, and denied accusations that he had betrayed the deposed president, Mohamed Morsi.

The army chief's speech came ahead of "national reconciliation" sessions called for by the interim leader Adly Mansour, and followed renewed violence in and outside the capital, in which at least three people died.

NJF/NJF