CAIRO (AP) -- Thousands of protesters denouncing Egypt's Islamist president marched on his palace in Cairo on Friday, clashing with security forces firing tear gas and water cannons in the eighth day of the country's wave of political violence.
Protests were held in cities around the country on Friday after a call for rallies by opponents of President Mohammed Morsi. But some cracks appeared in the ranks of the opposition as some sharply criticized its political leaders for holding their first meeting with the rival Muslim Brotherhood a day earlier.
Around 60 people have been killed in protests, rioting and clashes that engulfed the country the past week in country's worst crisis since the 2011 fall of autocrat Hosni Mubarak.
Around 6,000 protesters massed outside Morsi's presidential palace in an upscale district of the capital, banging on the gates and throwing stones and shoes into the grounds in a show of contempt. At least one firebomb was thrown through the gates as crowds chanted, "Leave, leave," addressing Morsi.
Security forces inside the palace responded by firing water cannons at the crowd, then volleys of tear gas. A tree inside the palace grounds caught fire. Riot police moved in outside the gates, sending the protesters scattering for cover, but then they surged back.
The streets outside the palace became a scene of mayhem as police fired volley after volley of tear gas trying to drive back the protesters, who rained stones on the riot police. Flames leaped as security forces set fire to protest tents, young men banged on metal fences and threw fireworks, and the beams of laser pointers danced in the smoke.
"This is all because of Morsi!" one protester shouted. At least 15 people were injured in the clashes, police said.
Thousands more rallied in central Tahrir Square, while a larger crowd marched through the Suez Canal city of Port Said, which witnessed the worst clashes and highest casualties, pumping their fists in the air and chanting, "Leave, leave, Morsi."
The wave of protests began around rallies marking the second anniversary of the uprising that toppled Mubarak. The unrest was prompted by public anger that Morsi and his Muslim Brotherhood are monopolizing power and have failed to deal with the country's mounting woes.
But outrage has been further fueled by Morsi's public backing of what was seen as security forces' use of excessive force against protesters last weekend, particular in Port Said, where around 40 people were killed.
Amid the escalating tensions the past week, there have been fears of direct clashes between Morsi's opponents and his Islamist backers. Such battles broke out at the palace in December during an earlier wave of unrest, when Islamists attacked an anti-Morsi sit-in, prompting fighting that left around 10 dead.
A Brotherhood spokesman, Ahmed Arif, underlined on Friday that the group would not call its cadres into the streets. But a young Brotherhood member said the group's members were ordered to gather in a mosque near the presidential palace, as a "precautionary measure" in case anti-Morsi protests turned violent. He spoke on condition of anonymity because he was not authorized to speak to the press.
The government, meanwhile, has increasingly blamed violence on a group of protesters called the Black Bloc, who wear black masks and have vowed to "defend the revolution." Officials and state media depict them as conspiratorial saboteurs, but the opposition says authorities are using the group as a scapegoat to justify a crackdown.
Nearly 20 masked protesters are among hundreds arrested around the country the past week. Egypt's official news agency said on Thursday that a member of the Black Bloc was arrested with "Israeli plans" and maps to target vital institutions - recalling past allegations by Mubarak-era security officials that opponents were carrying out Israeli interests.
"There's a great deal of exaggeration concerning the Black Bloc group," said Gamal Fahmy, an opposition figure. "It hasn't been proven that the group has committed violence, these are just calls over the social media."
"This is an attempt from the Muslim Brotherhood to blackmail the opposition," by depicting the anti-Morsi movement as violent, he said.
The eruption of violence prompted Morsi last Sunday to declare a state of emergency and curfew in Port Said and two other Suez Canal cities, where angry residents have defied the restrictions with nightly rallies.
Thousands marched on Friday through Port Said, located at the Canal's Mediterranean end, pumping their fists and chanting, "Leave, leave, Morsi." They threatened to escalate pressure with civil disobedience and a work stoppage at the vital Suez Canal authority if their demand for punishment of those responsible for protester death is not met.
"The people want the Republic of Port Said," protesters chanted, voicing a wide sentiment among residents that they are fed up of negligence and mistreatment by central government and that they want to virtual independence.
Buses brought protesters from the two other Suez Canal cities of Suez and Ismailia to join the Port Said rallies.
Friday marked the first anniversary of a mass soccer riot in Port Said that left 74 people dead, mostly fans of Al-Ahly, Egypt's most popular soccer team, which was playing a local Port Said team, Al-Masry.
The past weekend's violence in Port Said was sparked when a court convicted 21 people, mostly locals, in the soccer deaths, a verdict residents saw as unjust and political. Over the next few days, around 40 people were killed in the city in unrest that saw security forces firing on a funeral.
Egypt's main opposition political grouping, the National Salvation Front, called for Friday's protests in Cairo, demanding Morsi form a national unity government and amend the constitution, moves they say would prevent the Islamist from governing solely in the interest of his Muslim Brotherhood group.
"The policies of the president and the Muslim Brotherhood are pushing the country to the brink," the opposition said in a statement.
However, the call came a day after the Front held a meeting with Morsi's Muslim Brotherhood under the aegis of Egypt's premier Islamic institution, Al-Azhar, in their first ever meeting. They and other politicians signed a joint statement denouncing violence.
The meeting appeared to have caused rifts within the opposition, with some saying the Front had handed the Brotherhood the high ground by signing a statement that seemed to focus on protester violence and made no mention of police use of excessive force or explicitly talk of political demands.
"Al-Azhar's initiative talks too broadly about violence as if it's the same to kill a person or break a window and makes no difference between defensive violence and aggressive violence, offering a political cover to expand the repression, detention, killing and torture by the hands of police for the authority's benefit," read a joint statement by 70 activists, liberal politicians, actors and writers.
"The initiative didn't represent the core of the problem and didn't offer solutions but came to give more legitimacy to the existing authority," it added.
Those who attended the Thursday's rare meeting between Egypt's rival political camps defended the anti-violence initiative.
Egypt's leading pro-democracy advocate Mohammed ElBaradei and a Front leader described allegations that the Front is making political compromises them as "intentional attempt to split the ranks."
"We toppled down Mubarak regime with a peaceful revolution. We insist on achieving the goals the same way whatever the sacrifices and the barbaric suppression tactics," the Nobel peace Laureate tweeted.
Ahmed Maher, co-founder of April 6 group which led the anti-Mubarak uprising, said in a tweet: "I am against violence as a solution." An opposition party leader Ahmed Said said in a statement, "no one can say no to an initiative to stop violence."