Egypt's president has issued constitutional amendments granting himself far-reaching powers and ordering the retrial of leaders of Hosni Mubarak's regime for the killing of protesters in last year's uprising.

Mohammed Morsi also decreed immunity for the Islamist-dominated panel drafting a new constitution from any possible court decisions to dissolve it, a threat that had been hanging over the controversial assembly.

'Morsi today usurped all state powers & appointed himself Egypt's new pharaoh'— Mohamed ElBaradei, a pro-reform leader

Liberal and Christian members withdrew from the assembly during the past week to protest what they say is the hijacking of the process by Morsi's allies, who they say are trying to push through a document that will have an Islamist slant marginalizing women and minority Christians and infringing on personal liberties.

Morsi on Thursday extended by two months the deadline for the assembly to produce a draft for a new constitution, apparently to give members more time to iron out their differences.

Several courts have been looking into cases demanding the dissolution of the panel.

The Egyptian leader also decreed that all decisions he has made since taking office in June and until a new constitution is adopted and a new parliament is elected — which is not expected before next spring — are not subject to appeal in court or by any other authority. He also barred any court from dissolving the Islamist-led upper house of parliament.

'Egypt's new pharaoh'

The moves effectively remove any oversight on Morsi, the longtime Muslim Brotherhood figure who became Egypt's first freely elected president last summer after the Feb. 11, 2011 fall of autocrat Hosni Mubarak.

They come as Morsi is riding high on lavish praise from President Barack Obama and Secretary of State Hillary Rodham Clinton for mediating an end to eight days of fighting between Israel and Gaza's Hamas rulers.

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Egyptian protesters throw back tear gas canisters during clashes with security forces, near Tahrir Square in Cairo Wednesday. (Mohammed Asad/Associated Press)

Morsi not only holds executive power, he also has legislative authority after a previous court ruling just before he took office on June 30 dissolved the powerful lower house of parliament, which was led by the Brotherhood. With two branches of power in his hands, Morsi has had repeated friction with the third, the judiciary, in recent months.

"Morsi today usurped all state powers & appointed himself Egypt's new pharaoh," pro-reform leader Mohamed ElBaradei wrote on his Twitter account. "A major blow to the revolution that could have dire consequences."

ElBaradei later addressed a news conference flanked by other prominent politicians from outside the Brotherhood, including two presidential candidates who ran against Morsi, Amr Moussa and Hamdeen Sabahi.

They pledged to co-operate to force Morsi to rescind his assumption of greater powers. "We will work together as Egyptians until we achieve the goals of our revolution," said ElBaradei, a former director of the U.N.'s nuclear agency and Nobel peace laureate.

They called for mass protests Friday to demand the dissolution of the declarations. The audience interrupted the press conference, chanting "Down with the Guide's rule," referring to the Supreme Guide of Morsi's Muslim Brotherhood group, Mohammed Badie.

The prospect of large rival protests involving Morsi's opponents and supporters in Cairo on Friday raises the likelihood of clashes.

Protests in Cairo

The moves are likely to fuel growing public criticism that Morsi and his Muslim Brotherhood have monopolized power while doing little to tackle the country's endemic woes. Thousands of demonstrators gathered in downtown Cairo for the fourth day running to protest Morsi's policies and criticize the Brotherhood, the fundamentalist group from which the Egyptian leader hails.

The city centre had seen "running battles between riot police and angry demonstrators who say that President Morsi is not fulfilling the ambitions, the ideals, of the revolution," CBC's Margaret Evans reported from Cairo.

The decree for a retrial of Mubarak appeared aimed at making a gesture to the public. The decree called for "new investigations and trials" against those who held "political or executive" positions in the old regime and who are accused of killing protesters.

Mubarak was convicted in June and sentenced to life in prison for failing to stop the killing of protesters during last year's uprising against his rule. But many Egyptians were angered that he wasn't convicted of ordering the crackdown, and that his security chief, Habib el-Adly, was not sentenced to death.

Several top police commanders were acquitted, and Mubarak and his sons were found not guilty of corruption charges.

However, the decree would not mean retrials for the dozens of lower-level police officers who have been acquitted or received suspended sentences in trials for killing protesters — verdicts that have outraged many Egyptians.

That exclusion will guarantee Morsi the loyalty of the powerful but hated police force which had abandoned the streets for more than a year after Mubarak's ouster by a popular uprising motivated in large part by the human rights violations of the police and the notorious security services.

Country's top prosecutor fired

Morsi on Thursday also fired the country's top prosecutor, Abdel-Maguid Mahmoud, who has been in the job since 2006. A Mubarak-era appointee, Mahmoud has faced widespread accusations that his office did a shoddy job collecting evidence against Mubarak, el-Adly and the police commanders.

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Morsi, right, swears his new prosecutor general, Talaat Abdullah, left, in Cairo on Thursday. (Egyptian Presidency/Associated Press)

Morsi first fired Mahmoud in October but had to rescind his decision when he found that the powers of his office do not empower him to do so. So on Thursday, he decreed that the prosecutor general could serve in office only for four years, with immediate effect. Morsi replaced Mahmoud with Talaat Abdullah, a career judge.

Shortly before Morsi's decisions were announced, hundreds of Morsi supporters gathered outside Mahmoud's office chanting slogans against him and demanding the "cleansing of the judiciary."

Thursday's decisions were read on state television by Morsi's spokesman, Yasser Ali. In a throwback to the days of the authoritarian Mubarak and his predecessor Anwar Sadat and Gamal Abdel-Nasser, the television followed up with a slew of nationalist songs.

The introductions of the decrees declared that they were designed to "protect" the revolution and dismantle the old regime, a nod to the revolutionaries who have long complained that not enough was being done to reform the country after Mubarak's 29-year rule.

The president made most of the changes Thursday by issuing a declaration amending what has become a patchwork interim constitution in effect since Mubarak's fall. The military, which took power after Mubarak, set the precedent for the executive unilaterally issuing constitutional changes, which it did several times during its 16-month rule.

Morsi narrowly won the presidency — taking about 52 per cent of the vote — to become Egypt's first freely elected and civilian president, ending nearly six decades of de facto military rule.

With files from CBC News