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* Politicians disavow violence but still call for marches
* Nearly 60 people killed since Jan 25
* Opponents accuse Mursi of consolidating power
* Brotherhood says opposition trying to undo election outcome
By Alexander Dziadosz and Seham Eloraby
CAIRO/PORT SAID, Egypt, Feb 1 (Reuters) - Thousands of opponents of President Mohamed Mursi returned to the streets of Egypt on Friday, demanding his overthrow after the deadliest violence of his seven months in power.
Men in black shirts of mourning marched through the Suez Canal city of Port Said, scene of the worst bloodshed of the past 9 days, chanting and shaking fists.
"There is no God but God and Mohamed Mursi is the enemy of God," they chanted. Holding aloft portraits of those killed in the latest violence, they shouted: "We will die like they did, to get justice!"
Protests marking the second anniversary of the uprising that toppled Hosni Mubarak have killed nearly 60 people since Jan. 25, prompting the head of the army to warn this week that the state was on the verge of collapse.
For the Port Said marchers, Friday was also the first anniversary of a soccer stadium riot that killed 70 people last year. Death sentences handed down on Saturday against 21 Port Said people over the riots fueled the past week's violence there, which saw dozens shot dead in clashes with police.
Mursi imposed a curfew and emergency rule in Port Said and two other canal cities on Sunday, a move that only seems to have added to the sense of grievance there.
Protesters also marched in Alexandria, Ismailia and the capital Cairo, where they were expected to descend on the presidential palace. Mursi's supporters have clashed with protesters at the palace in the past, although the Brotherhood has kept its men off the streets in recent days.
The protesters accuse Mursi of betraying the spirit of the revolution by concentrating too much power in his own hands and those of his Muslim Brotherhood. The Brotherhood accuses the opposition of trying to overthrow the first democratically elected leader in Egypt's 7,000-year history.
Friday's marches took place despite an intervention by Sheikh Ahmed al-Tayyeb, head of the 1,000-year-old al-Azhar university and mosque, who hauled in rival political leaders for crisis talks on Thursday and persuaded them to sign a charter disavowing violence. Anti-Mursi politicians said that pact did not require them to call off demonstrations.
"We brought down the Mubarak regime with a peaceful revolution and are determined to realise the same goals in the same way, regardless of the sacrifices or the barbaric oppression," tweeted Mohamed ElBaradei, a former head of the U.N. nuclear watchdog who has become a secularist leader.
In a statement released overnight, leftist leader Hamdeen Sabahi said despite the Azhar initiative he would not enter talks until bloodshed was halted, a state of emergency lifted and those to blame for the violence brought to justice.
"Our aim ... is to complete the goals of the glorious January revolution: bread, freedom and social justice," he said.
MONUMENT TO TURMOIL
Tahrir Square, ground zero of last year's revolution against Mubarak, has become a graffitti-scrawled monument to Egypt's perpetual turmoil, strewn with barbed wire and burnt out cars. Hundreds of protesters gathered in the rain as vendors sold flag bracelets, pharaonic statues, sunflower seeds and water.
A man with a microphone shouted to a crowd of a few hundred, calling for Mursi to be put on trial.
"We came here to get rid of Mursi," said furniture dealer Mohammed al-Nourashi, 57. "He's only a president for the Brotherhood." As he spoke, a crowd gathered.
"Why is Obama supporting Mursi and the Brotherhood? Why?" a man shouted, challenging the U.S. president's policy in Egypt.
Osama Mohammed, 24, selling fruit from a battered wooden cart, said he graduated with a degree in commerce in 2007, but hadn't been able to find work - the sort of economic problems that caused the 2011 uprising and have only gotten worse since. He was not on the square for politics, just business.
"I've come every Friday because there's traffic," he said. "If the protests stay peaceful, it's no problem."
The rise of Mursi, an elected Islamist, after generations of rule by authoritarian, secular military men in the most populous Arab state, is probably the single most important change of the past two years of Arab popular revolts.
But seven months since taking power after a narrow election victory over a former general, Mursi has failed to unite Egyptians and protests have made the country seem all but ungovernable. The instability has worsened an economic crisis, forcing Cairo to drain currency reserves to prop up its pound.
It is far from clear that opposition politicians could call off the street demonstrations, even if they wanted to. The protest movement has become a spontaneous expression of rage, often only loosely allied to secularist and liberal parties.
"You have groups who clearly just want a confrontation with the state - straightforward anarchy; you've got people who supported the original ideals of the revolution and feel those ideals have been betrayed," said a diplomat. "And then you have elements of the old regime who have it in their interests to foster insecurity and instability. It is an unhealthy alliance."
Many Egyptians are fed up with the violence.
"We are exhausted. This protests thing is a political game whose price the people are paying. I hate them all - liberals and Brotherhood," said Abdel Halim Adel, 60, near the presidential palace.
Hamdy Mohamed, 40, was warily taking his family out for Friday weekend lunch. "We no longer look to Fridays as a fun day off, but we fear it," he said. "That is very frustrating, especially for people like me with kids who need to go out and play. I can't do that on my weekend because of this mess." (Additional reporting by Tom Perry and Yasmine Saleh in Cairo and Yusri Mohamed in Ismailia; Writing by Peter Graff; Editing by Paul Taylor)