CAIRO -- More than 200,000 people thronged Cairo's central Tahrir Square, protesting against Egypt's Islamist president Tuesday in an opposition show of strength, as the standoff over Mohammed Morsi's assertion of near-absolute powers escalated into the biggest challenge yet to his and the Muslim Brotherhood's rule.
The massive, flag-waving, chanting crowd in the iconic plaza rivaled the size of some of the large protests of last year's uprising that drove autocrat Hosni Mubarak from office. The same chants used against Mubarak were now turned against Egypt's first freely elected leader.
"The people want to bring down the regime," and "erhal, erhal" -- Arabic for "leave, leave," rang across the square.
Protests in Tahrir and several other cities Tuesday were sparked by edicts issued by Morsi last week that effectively neutralized the judiciary, the last branch of government he does not control. But it turned into a broader outpouring of anger against Morsi and the Muslim Brotherhood, which opponents say have used election victories to monopolize power, squeeze out rivals, and dictate a new, Islamist constitution, while doing little to solve Egypt's mounting economic and security woes.
Clashes broke out in several cities as Morsi opponents tried to attack offices of the Brotherhood, setting fire to at least one. At least 100 people were injured when protesters and Brotherhood members protecting their office pelted each other with stones and firebombs in the Nile Delta city of Mahalla el-Kobra.
"Power has exposed the Brotherhood. We discovered their true face," said Laila Salah, a housewife in the Tahrir protest who said she voted for Morsi in this summer's presidential election. After Mu barak, she said, Egyptians would no longer consent to an autocrat.
"It's like a wife whose husband was beating her and then she divorces him and becomes free," she said. "If she remarries she'll never accept another day of abuse."
Gehad el-Haddad, a senior adviser to the Brotherhood and its political party, said Morsi would not back down on his edicts. "We are not rescinding the declaration," he told The Associated Press.
That sets the stage for a drawn-out battle between the two sides that could throw the nation into greater turmoil. Protest organizers on a stage in the square called for another mass rally on Friday. If the Brotherhood responds with mass rallies of its own, as some of its leaders have hinted, it would raise the prospect of greater violence after a series of clashes between the two camps in recent days.
A tweet by the Brotherhood warned that if the opposition was able to bring out 200,000-300,000 "they should brace for millions in support" or Morsi.
Another flashpoint could come Sunday, when the constitutional court is due to rule on whether to dissolve the assembly writing the new constitution, which is dominated by the Brotherhood and Islamist allies. Morsi's edicts explicitly banned the courts from disbanding the panel. If the court defies him and rules anyway, it would be a direct challenge that could spill over into the streets.
"Then we are in the face of the challenge between the supreme court and the presidency," said Nasser Amin, head of the Arab Center for the Independence of the Judiciary and the Legal Profession. "We are about to enter a serious conflict" on both the legal and street level, he said.
Morsi and his supporters say the decrees were necessary to prevent the judiciary from blocking the "revolution's goals" of a transition to demo cracy. The courts -- where many Mubarak-era judges still hold powerful posts -- already disbanded the first post-Mubarak elected parliament, which was led by the Bro therhood. The judiciary has also been considering whether to dissolve both the constitutional assembly and the Islamist-led upper house of parliament.
Tuesday's turnout was an un precedented show of strength by the mainly liberal and secular opposition, which has been divided and uncertain amid the rise to power of the Bro therhood over the past year.
The crowds were of all stripes, including many first-time protesters.
"Suddenly Morsi is issuing laws and becoming the absolute ruler, holding all powers in his hands," said protester Mona Sadek, a 31-year-old engineering graduate who wears the Islamic veil, a hallmark of piety. "Our revolt against the decrees became a protest against the Brotherhood as well."
Raafat Magdi, an engineer, said, "We want to change this whole setting. The Brotherhood hijacked the revolution."
"People woke up to his (Morsi's) mistakes, and in any new elections they will get no votes," said Magdi, who was among a crowd of around 10, 000 marching from the Cairo district of Shubra to Tahrir to the beat of drums and chants against the Brotherhood. Reform leader Mohammed ElBaradei led the march.
Many said they were determined to push ahead with the protests until Morsi retreats. A major concern among the protesters was that Islamists would use the decree's protection of the constitutional assembly to drive through their vision for the next charter, with a heavy emphasis on implementing Shariah, or Islamic law. The assembly has been plagued with controversy, and more than two dozen of its 100 members have quit in recent days to protest Islamist control.
"Next Friday will be decisive," protester Islam Bayoumi said of the upcoming planned rally. "If people maintain the same pressure and come in large numbers, they could manage to press the president and rescue the constitution."
A fellow protester, Saad Salem Nada, said of Morsi, "I am a Muslim and he made me hate Muslims because of the dictatorship in the name of religion. In the past, we had one Mubarak, now we have hundreds."
Even as the crowds swelled in Tahrir, clashes erupted nearby between several hundred young protesters throwing stones and police firing tear gas on a street off Tahrir leading to the U.S. Embassy. Clouds of tear gas hung close to the ground at the area. Clashes have been taking place at the site for several days, fueled by anger over police abuses, separately from the crisis over Morsi.
A photographer working for the AP, Ahmed Gomaa, was heavily beaten by police using sticks while covering the clashes Tuesday. Police took his equipment, and Gomaa was taken to hospital for treatment.
Rival rallies by Morsi opponents and supporters turned into brief clashes in the Mediterranean city of Alexandria, then anti-Morsi protesters broke into the local office of the Muslim Brotherhood, throwing furniture out the windows and trying unsuccessfully to set fire to it. Protesters also set fire to Brotherhood offices in the city of Mansoura.
Morsi's supporters canceled a massive rally they had planned for Tuesday in Cairo, citing the need to "defuse tension." Morsi's supporters say more than a dozen of their offices have been ransacked or set ablaze since Friday. Some 5,000 demonstrated in the southern city of Assiut in support of Morsi's decrees, according to witnesses there.
So far, there was little sign of a compromise in the crisis. On Monday, Morsi met with the nation's top judges and tried to win their acceptance of his decrees. But the move was dismissed by many in the opposition and the judiciary as providing no real concessions.
Saad Emara, a senior Muslim Brotherhood member, said Morsi will not make any concessions, especially after the surge of violence and assaults on Muslim Brotherhood offices.
Emara ccused the opposition "of resorting to violence and with a political cover," claiming that former ruling party and Mubarak-era businessmen are hiring thugs to attack Brotherhood offices with the opposition's blessing.
"The story now is that the civilian forces are playing with fire. This is dangerous scene."
AP correspondents Hamza Hendawi contributed to this report.