The Egyptian judiciary intensified its resistance Wednesday to a move last week by President Mohamed Morsi to greatly enlarge his power, as the country’s top courts joined a growing number of striking judges in expressions of dissent.

Egypt’s highest appeals court, known as the Court of Cassation, suspended work in protest of the edict authorizing Morsi to legislate without judicial oversight. The Supreme Constitutional Court accused the president, an Islamist backed by the Muslim Brotherhood, of participating in an attack on the justice system.

Morsi’s move, which opposition groups and political analysts have deemed a power grab, set off a nationwide wave of protests, culminating in a rally in Cairo’s Tahrir Square on Tuesday night in which tens of thousands called for the president’s ouster. On Wednesday, protesters still clashed sporadically with security forces on the fringes of the square.

The crisis has underscored the deepening polarization of Egypt’s political classes as the country struggles to define a new body of laws and the nature of its religious identity two years after a popular uprising forced longtime autocrat Hosni Mubarak from power.

At the center of the turmoil is Egypt’s nascent constitution. The assembly tasked with drafting the charter has been dominated by Islamists — a reflection of the country’s first democratically elected parliament, which was dissolved by a court order this year.

But liberals and secularists say that the constituent assembly does not adequately represent them and accuse it of seeking to implement Islamic law through the charter. Many have seized on the outrage over Morsi’s decree as an opportunity to rally wider support against Islamist rule.

The head of the assembly said Wednesday that a final draft of the constitution would soon be ready, with a vote expected Thursday. If approved, the document would be put to a public referendum.

But opposition leaders said Wednesday that the move by the Muslim Brotherhood-led committee to push forward with the draft amid the crisis would be a grave mistake.

The assembly “doesn’t express Egyptians now, and morally and politically it’s already been dissolved,” said Hamdeen Sabahi, a prominent secular politician and one of the top contenders for Egypt’s presidency in the summer. “But if they insist on completing the draft from one side and only one faction of Egyptians — the Muslim Brotherhood — it means it won’t even be a constitution.”

Egypt’s crisis would only deepen, Sabahi added, “and, of course, we will refuse that.”

The crisis has pitted Morsi and his Islamist supporters against not only a justice system still dominated by Mubarak appointees but also an unlikely alliance of human rights groups, liberal youth activists and the old-regime loyalists they once opposed.

Opposition leaders said they planned to hold more marches Thursday and Friday, and the Muslim Brotherhood called for a rival nationwide demonstration in support of the edict Saturday.

Meanwhile, the Supreme Constitutional Court, the country’s highest judicial power, vowed to resist what it characterized as an attempt by Morsi to undermine the court system.

“The court will not be intimidated by any threats or blackmail and will not submit to any pressures practiced on it from any direction, regardless of its power and unity,” Maher Samy, the court’s spokesman, said at a news conference.

The court also vowed to examine the legality of Morsi’s action.

The president and his supporters say the decree was necessary to safeguard the democratic gains of Egypt’s uprising. The declaration included the removal of the country’s deeply unpopular general prosecutor, a Mubarak appointee, and the protection of the constitution-drafting assembly against the possibility of a court-ordered dissolution.

And Essam el-Erian, a leader of the Muslim Brotherhood’s Freedom and Justice Party, pushed back Wednesday against the constitutional court’s statement.

“The judges’ partisan entry into the current debates is harmful to the process of democratization,” Erian tweeted an hour after the court’s news conference. “The Egyptian judiciary is above politics and partisanship.”

Morsi’s spokesman attempted to clarify the controversial decree Monday night, saying that it is temporary and renders only “acts of sovereignty” immune from judicial appeal.

For many of Morsi’s opponents, however, the decree merely confirms their fear that the Muslim Brotherhood is seeking to replicate a decades-old authoritarian regime, rather than help Egypt make the transition to democracy.

“Whoever does not respect the judiciary is not fit to rule Egypt,” said Ekramy al-Sayed Abdou, a protester in Tahrir Square on Tuesday night.

But even as the protests dragged into a sixth day, analysts said the high stakes for both sides mean that some type of compromise is likely.

Yasser el-Shimy, an Egypt analyst for the International Crisis Group, said the protests have transformed the country’s normally fractious liberal and secular opposition into a more unified and effective “pressure group.” At the same time, he said, any serious reversal by Morsi will cost him his credibility.

“If he were to back away now, he would be finished as a president,” Shimy said.

More likely, the analyst predicted, Morsi and the judiciary will reach a compromise in which the president gets to keep some elements of the decree, such as the protection of the constituent assembly and the elected upper house of parliament against court efforts to dissolve them, while backing off his claim for total legislative control.

Sabahi, court officials and others said Wednesday that they would not accept anything short of a full retreat.

Ingy Hassieb contributed to this report.