Supporters of President Mohammed Morsi clashed with opponents in Cairo's Tahrir Square on Friday in the worst violence over Egypt's new Islamist leader, a day after he crossed swords with the judiciary.

Morsi's Muslim Brotherhood movement and a coalition of secular-leaning groups held separate rallies on some of the thorniest issues facing the new democracy after last year's uprising which ousted president Hosni Mubarak.

Egypt's public prosecutor refused to resign on Thursday after President Mohammed Morsi ordered his removal to allay public anger over the acquittals of Mubarak-era officials.

"I remain in my post," Abdel Meguid Mahmud told reporters. "According to the law, a judicial body cannot be dismissed by an executive authority."

Egypt's Muslim Brotherhood on Thursday called for demonstrations demanding the retrial of those responsible for protester deaths during last year's popular uprising against Hosni Mubarak.

A court on Wednesday acquitted 24 stalwarts of the ousted president who had been accused of incitement to murder over a notorious camel-borne assault on protesters on February 2, 2011, to the disbelief of human rights activists.

Egypt's Supreme Administrative Court on Tuesday postponed a decision on the fate of the Constituent Assembly that is tasked with drafting the country's new constitution.

A ruling had been widely expected on Tuesday but Judge Farid Nazih put off the hearing to October 16 to review more documents, judicial officials said.

Egyptian President Mohamed Morsi's decision to pardon protesters detained over the 2011 revolution is a positive step but the vague wording could see some left behind bars, rights activists said on Tuesday.

"It's a very good decision but the distinction between a political detainee and a criminal one is fundamentally problematic," said Heba Morayef, a Cairo-based researcher with Human Rights Watch.

Egypt's President Mohammed Morsi on Monday pardoned all those arrested between the start of the revolution that toppled president Hosni Mubarak in February 2011 and June this year, state media said.

A decree published on the presidency's official Facebook page announced the amnesty for deeds "committed with the aim of supporting the revolution and bringing about its objectives, in the period January 25, 2011 to June 30, 2012, with the exception of crimes of first-degree murder."

A draft Egyptian constitution heavily influenced by Islamist conservatives contains articles that could pose a serious threat to basic human rights in post-Mubarak Egypt, Human Rights Watch said on Monday.

A 100-strong panel picked in June and headed by senior judge Hossam al-Ghariani has been tasked with drafting the new constitution, after the old charter was suspended following the 2011 uprising which toppled Hosni Mubarak.

Nineteen Egyptian policemen were killed in an accident on Monday after their driver lost control of their truck in the Sinai, where security forces are battling Islamist militants, state media reported.

Another six policemen were injured in the accident near the border with Israel, the official MENA news agency reported.

Mitt Romney will call for a U.S. change of course in the Middle East on Monday, saying President Barack Obama's muddled strategy has failed to confront the challenges of extremism.

The Republican White House hopeful, offering a foreign policy vision that he and his campaign believe differs sharply from Obama's, said he would keep Iran in check, chase terrorists in Libya, put conditions on U.S. aid to Egypt and help arm Syrian rebels.

Radical Islamist preacher Abu Hamza and four other terrorism suspects are set to be extradited to the United States after a British court Friday rejected their last-ditch attempts to block their removal.

A legal saga that has dragged on for more than a decade in the courts of Britain and Europe finally ended when two senior judges at the High Court in London dismissed the men's pleas to be allowed a stay of extradition.