CAIRO (AP) -- Egypt descended into political turmoil on Wednesday over the constitution drafted by Islamist allies of President Mohammed Morsi, and at least 211 people were wounded as supporters and opponents battled each other with firebombs, rocks and sticks outside the presidential palace.
Four more presidential aides resigned in protest over Morsi's handling of the crisis, and a key opponent of the Islamist president likened Morsi's rule to that of ousted authoritarian leader Hosni Mubarak.
Both sides were digging in for a long struggle, with the opposition vowing more protests and rejecting any dialogue unless the charter is rescinded, and Morsi pressing relentlessly forward with plans for a Dec. 15 constitutional referendum.
"The solution is to go to the ballot box," declared Mahmoud Ghozlan, a spokesman for Morsi's Muslim Brotherhood, asserting the charter was "the best constitution Egypt ever had."
The clashes outside the presidential palace in Cairo's Heliopolis district marked an escalation in the deepening crisis. It was the first time supporters of rival camps fought each other since last year's anti-Mubarak uprising, when the authoritarian leader's loyalists sent sword-wielding supporters on horses and camels into Cairo's Tahrir square in what became one of the uprising's bloodiest days.
The large scale and intensity of the fighting marked a milestone in Egypt's rapidly entrenched schism, pitting Morsi's Brotherhood and ultra-conservative Islamists in one camp, against liberals, leftists and Christians in the other.
The violence spread to other parts of the country later Wednesday. Anti-Morsi protesters stormed and set ablaze the Brotherhood offices in Suez and Ismailia, east of Cairo, and there were clashes in the industrial city of Mahallah and the province of Menoufiyah in the Nile Delta north of the capital.
Compounding Morsi's woes, four of his advisers resigned, joining two other members of his 17-member advisory panel who have abandoned him since the crisis began.
Mohamed ElBaradei, a leading opposition reform advocate, said Morsi's rule was "no different" than Mubarak's.
"In fact, it is perhaps even worse," the Nobel Peace Prize laureate told a news conference after he accused the president's supporters of a "vicious and deliberate" attack on peaceful demonstrators outside the palace.
"Cancel the constitutional declarations, postpone the referendum, stop the bloodshed, and enter a direct dialogue with the national forces," he wrote on his Twitter account, addressing Morsi.
"History will give no mercy and the people will not forget."
The opposition is demanding that Morsi rescind the decrees giving him nearly unrestricted powers and shelve the controversial draft constitution the president's Islamist allies rushed through last week in a marathon, all-night session shown live on state TV.
The huge scale of the opposition protests has dealt a blow to the legitimacy of the new charter, which Morsi's opponents contend allows religious authorities too much influence over legislation, threatens to restrict freedom of expression and opens the door to Islamist control over day-to-day life.
In addition, the country's powerful judges say they will not take on their customary role of overseeing the referendum. Zaghloul el-Balshi, secretary general of the state committee organizing the referendum, said on the private Al-Hayat television that he would not go ahead with preparations for the vote until the fighting stopped and Morsi rescinded his decrees.
The country's new attorney general, a Morsi appointee, hit back, ordering an investigation of Ahmed El-Zind, chairman of the judges' union that is spearheading the call for a boycott.
Wednesday's clashes began when thousands of Morsi's Islamist supporters descended on an area near the presidential palace where some 300 of his opponents were staging a sit-in. The Islamists, members of Morsi's Muslim Brotherhood, chased the protesters away from their base outside the palace's main gate and tore down their tents.
The protesters scattered into side streets, where they chanted anti-Morsi slogans as the Islamists shouted, "The people demand the implementation of God's law!"
After a brief lull, hundreds of Morsi opponents arrived and began throwing firebombs at the president's backers, who responded with rocks. The clashes continued well after nightfall and spread from the immediate vicinity of the palace to residential streets nearby.
The deployment of hundreds of riot police did not stop the fighting. The police later fired tear gas to disperse Morsi's opponents. Volunteers ferried the wounded on motorcycles to waiting ambulances, which rushed them to hospitals.
"I voted for Morsi to get rid of Hosni Mubarak. I now regret it," Nadia el-Shafie yelled at Brotherhood supporters on a side street.
"God is greater than you! Don't think this power or authority will add anything to you. God made this revolution, not you!" the tearful woman said as she was led away from the crowd of Islamists.
"May God protect Egypt and its president," read a banner hoisted atop a truck brought by the Islamists, as a man using a loudspeaker recited verses from the Quran.
"We came to support the president. We feel there is a legitimacy that someone is trying to rob," said Rabi Mohammed, a Brotherhood supporter. "People are rejecting democratic principles using thuggery."
The Islamists portrayed their attack on opposition protesters as defense of the revolution.
The clashes, said top Brotherhood leader Essam el-Erian, pitted "those who are protecting the legitimacy and the revolution against the counterrevolution and coup plotters."
Vice President Mahmoud Mekki called for a dialogue with the opposition to reach a consensus on disputed articles of the constitution, which he put at 15 out of a total of 234. The referendum must go ahead, he said, adding that he was acting in a personal capacity, not on behalf of Morsi.
Speaking to reporters, ElBaradei said there would be no dialogue unless Morsi rescinded his decrees and shelved the draft constitution.
Asked to comment on Mekki's offer, he said: "With all due respect, we don't deal with personal initiatives. If there is a genuine desire for dialogue, the offer must come from President Morsi."
Morsi's Nov. 22 decrees were followed last week by the constitutional panel pushing through the draft constitution without the participation of liberal and Christian members. Only four women, all Islamists, attended the session.
If the referendum goes ahead as scheduled and the draft constitution is adopted, elections for parliament's lawmaking lower chamber will be held in February.
AP reporters Maggie Michael and Sarah El Deeb contributed to this report.
© 2012 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.