A crackdown on the Muslim Brotherhood movement got underway in Egypt on Thursday with the arrest of several leading members following the military overthrow of Islamist President Mohammed Morsi and his replacement by a top judge.
A leading member of the Muslim Brotherhood warned that the ouster of Morsi, a member of the movement, could prompt some groups to resort to violence, although he said the Brotherhood wouldn't do so. A coalition led by the Brotherhood called on Egyptians to mobilize peacefully in a "Friday of Rejection."
A military source told Reuters: "We will continue to secure the places of protest with troops, and jets if necessary, to make sure the pro- and anti-Mursi demonstrators don't confront each other. We will let them demonstrate and go where they want."
The deposed president was under house arrest at the Republican Guard Club, and most members of presidential team had also been placed under house arrest, a Brotherhood spokesman said.
Judge Tharwat Hammad said Thursday that judicial authorities had opened an investigation into accusations that Morsi and eight other senior leaders of the Muslim Brotherhood had defamed the judiciary. All were banned from traveling. The prosecutor expects to question Morsi some time next week.
A prosecutor also ordered the arrest of the Muslim Brotherhood's supreme guide, Mohammed Badie, and a top deputy, Khairat el-Shater, for allegedly ordering the killing of protesters outside the Brotherhood's headquarters Sunday, judicial sources said. It wasn't known where the two men were.
The action was taken as a judge appointed to Egypt's constitutional court by Hosni Mubarak — the strongman leader ousted by the Arab Spring uprising — was sworn in as interim president Thursday.
Adly Mansour, chairman of the Supreme Constitutional Court, pledged to look after the interests of "the great people of Egypt," promised new elections and urged the revolutionaries who helped topple Morsi to stay in Cairo's Tahrir Square.
Mansour, 67, said he would respect the rule of law and "look after the interests of the people," according to a live translation by BBC News.
He said he had received an "order" to become interim president from "the great people of Egypt" and that Egypt should stop producing "tyrants" and worship only God, not "any president."
"We look forward to hold presidential and parliamentary elections based on a genuine people's will," Mansour said.
Shortly afterward, he told journalists that the Muslim Brotherhood was "invited to participate in building the nation, as nobody will be excluded," Reuters reported.
The National Coalition in Support of Legitimacy, a coalition led by the Brotherhood, said its "Friday of Rejection" was meant to say "'No' to the military coup."
Sheikh Abdel Rahman al-Barr, a member of the Brotherhood's executive board, said Thursday that the movement wouldn't work with "the usurper authorities."
"We call on protesters to show self-restraint and stay peaceful. We reject the oppressive, police state practices: killing, arrests, curbing media freedom and closing TV channels," he added.
Mohamed Beltagy, a leading member of the Brotherhood's political arm, the Freedom and Justice Party, told reporters that Morsi's overthrow could lead to violence — although not by his group.
"The issue now is the position of the free world that is pushing the country to a state of chaos and pushing groups other than the Brotherhood to return to the idea of change by force," he said.
He said Morsi's followers hadn't resorted to violence but "our leaders and youths were killed, our offices — and even our homes — stormed, ransacked, burned and totally destroyed — not to mention the insults and obscenities we had to suffer."
The Brotherhood said a "new era of repression and tyranny, of an impending authoritarian police state" had begun, according to the Brotherhood's website, with TV channels shut down, arrests of politicians and "many citizens killed as they demonstrated peacefully."
A statement from Morsi's office's Twitter account Wednesday quoted the deposed president as saying the military's measures "represent a full coup categorically rejected by all the free men of our nation."
The U.S. was keeping a close eye on developments. President Barack Obama met with top advisers in the White House Situation Room to discuss the crisis Thursday, and members of his national security team "have been in touch with Egyptian officials and our regional partners to convey the importance of a quick and responsible return of full authority to a democratically elected civilian government," the White House said in a statement.
The State Department ordered "the departure of non-emergency U.S. government personnel and family members from Egypt due to the ongoing political and social unrest."
It remained unclear whether the U.S. would define the military's decision to oust Morsi as a coup. This could affect the $1.5 billion in aid given to Egypt annually.
U.S. law bans military or financial assistance "to the government of any country whose duly elected head of government is deposed by military coup or decree."
Obama said in a statement that he had "directed the relevant departments and agencies to review the implications under U.S. law for our assistance to the government of Egypt."
The Egyptian army insisted that it hadn't carried out a coup but had acted on the will of the people to clear the way for a new leadership.
The Associated Press and Reuters contributed to this report.