Egypt's stock market plunged nearly 10 percent Sunday in its first day open since President Mohamed Morsi seized new powers that set off street violence. Meanwhile, the Muslim Brotherhood is calling for nationwide demonstrations in support of the Islamist leader.

The losses on the Egyptian exchange are among the biggest since the turbulent days and weeks after the ouster of authoritarian leader Hosni Mubarak last year.

Mr. Morsi's Muslim Brotherhood supporters are expected to turn out again on the streets in a show of support after prayers on Sunday afternoon.

Earlier Sunday, protesters in Cairo's Tahrir Square, the site of the 2011 uprising that toppled Mubarak, threw rocks at police. Security forces fired back with rounds of tear gas in the third day of violence since the president's decrees put him above judicial oversight and extended the same protection to two Islamist-dominated bodies — the assembly writing a new constitution and the upper house of parliament.

President Morsi's supporters and opponents are both planning demonstrations on Tuesday that many fear will lead to more violence.

Prominent Egyptian democracy advocate Mohammed ElBaradei called Saturday for President Morsi to rescind the near absolute powers he has granted himself.

ElBaradei, addressing crowds in Tahrir Square, said the president must take the action to avoid the possibility of increased turmoil in the country that has recently shed its longtime repressive government.

Egypt's highest body of judges, the Supreme Judicial Council, also condemned President Morsi's decree.

The judges Saturday called the move “an unprecedented attack” on the independence of the judiciary. Judges in Alexandria have gone on strike, saying they will not return to work until the decree is withdrawn.

The protests began Friday, a day after President Morsi declared that his decisions cannot be appealed by the courts or any other authority. He cited a need to protect the achievements of the 2011 revolution that led to the ouster of Mubarak after three decades in power.

Mr. Morsi's decree Thursday includes an order for retrials of former officials who used violence to suppress last year's popular revolution against Mubarak. It also bars Egypt's judiciary from dissolving the upper house of parliament and an assembly drafting a new constitution – both dominated by the Muslim Brotherhood.