CAIRO (AP) — 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.

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 Mubarak, she said, Egyptians would no longer consent to an autocrat.

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.

Morsi and his supporters say the decrees were necessary to prevent the judiciary from blocking the “revolution’s goals” of a transition to democracy. The courts — where many Mubarak-era judges still hold powerful posts — already disbanded the first post-Mubarak elected parliament, which was led by the Brotherhood. The judiciary has also been considering whether to dissolve both the constitutional assembly and the Islamist-led upper house of parliament.

Morsi’s decrees Thursday banned the judiciary from doing so and gave any decisions issued by Morsi immunity from judicial review. Morsi also gave himself sweeping powers to take action to prevent threats to the revolution, stability or state institutions, which critics say are tantamount to emergency laws. The powers would last until the constitution is approved and parliamentary elections are held, not likely before spring 2013.

Opponents say the decrees turn Morsi — who narrowly won last summer’s election with just over 50 percent of the vote — into a new dictator, given that he holds not only executive power but also legislative, after the lower house of parliament was dissolved.

Tuesday’s turnout was an unprecedented show of strength by the mainly liberal and secular opposition, which has been divided and uncertain amid the rise to power of the Brotherhood over the past year. The crowds were of all stripes, including many first-time protesters.

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.

“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.”

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.

– Maggie Michael and Sarah El Deeb, Associated Press