CAIRO -- Egypt braced for fresh protests after Friday prayers as the opposition coalition planned to meet to review President Mohammed Morsi’s call for dialogue to resolve a crisis triggered by his decision to expand his powers.

In a televised speech late Thursday, Morsi proposed a meeting Saturday with political leaders, "revolutionary youth" and legal figures to discuss the way forward after a referendum on a new constitution set for Dec. 15.

Seven people were killed and hundreds injured this week in clashes around the presidential palace.

They were sparked by Morsi's Nov. 22 decree awarding himself extra powers and his decision to rush through a new constitution, written by an Islamist-dominated assembly that was opposed by liberals and others.

"We have decided to meet this afternoon (Friday) and discuss the whole issue and the proposal and speech by the president. We want a collective stand on that," the National Salvation Front’s Amr Moussa, a presidential candidate and former Arab League chief, told Reuters, adding the precise time had yet to be finalized.

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Opposition groups have called for protests Friday against Morsi and his decree. One prominent protest movement has already rejected the president's offer of talks.

Among the demands of the liberal-leaning National Salvation Front, Moussa said the opposition coalition believed a referendum on a draft constitution should be delayed.

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The Front would also consider Morsi's comments suggesting he was ready to reconsider elements of his decree. "The mood is still very solid on the demands that we have expressed and stressed," Moussa said.

The Front has previously demanded Morsi scrap his decree, postpone the referendum and redraft the constitution.

Obama calls Morsi

President Barack Obama called Morsi on Thursday to express his deep concern about the deaths and injuries of protesters in Egypt, the White House said in a statement.

“The President emphasized that all political leaders in Egypt should make clear to their supporters that violence is unacceptable,” the statement read. “Obama welcomed President Morsi's call for a dialogue with the opposition but stressed that such a dialogue should occur without preconditions.”

The United States has also urged opposition leaders to join the dialogue without preconditions.

More Egypt coverage from NBC News

The large scale and intensity of this week’s fighting marked a milestone in Egypt's rapidly emerging schism, pitting the Muslim Brotherhood and ultra-conservative Islamists in one camp, against liberals, leftists and Christians in the other.

It was the first time supporters of the rival camps have fought each other since last year's uprising that toppled authoritarian ruler Hosni Mubarak.

Reuters and The Associated Press contributed to this report.

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