Sarah Lynch, Special for USA TODAY
CAIRO - Egypt's top judge, Adly Mansour, was sworn in as the nation's interim president Thursday as the country grapples with uncertainty over its future, and as deposed leader Mohammed Morsi is under house arrest at an undisclosed location.
Mansour will be Egypt's interim president until a new election is held in the months ahead. A date for the vote has not been set.
In his first remarks as the country's new leader, Mansour, 67, who is the head of the High Constitutional Court, praised the massive street demonstrations that led to Morsi's ouster. He also hailed the youth behind the protests that began on June 30, saying they embodied "the nation's conscience, its ambitions and hopes."
"The most glorious thing about June 30 is that it brought together everyone without discrimination or division," he said. "I offer my greetings to the revolutionary people of Egypt."
After days of widespread unrest that brought unprecedented numbers to Egypt's streets, the army suspended the nation's constitution and called for new elections. The momentous upheaval effectively ousted Morsi, the nation's first democratically elected leader, and set the nation on a precarious path of transition.
On Wednesday, the capital exploded in celebration, with fireworks erupting across the sky and thousands crowding into Tahrir Square. Flags waved from countless windows. A mood of recklessness was also evident as cars whipped unpatrolled through Cairo's streets.
There was a sense of unease as reality set in that the nation's first freely elected leader was pushed from power.
STORY: Egyptians celebrate in the streets, but instability remains
"It is going the wrong way. It's a shame," said one Muslim Brotherhood supporter, Ahmed Hassan, concerned that the military does not respect human rights, and who fears sweeping arrests, which have already started.
The Brotherhood's political party chief and deputy chief were arrested early Thursday, the Associated Press reported. The movement's television station and other Islamist channels have also been cut and some Brotherhood figures are barred from leaving the country.
Morsi rose to the presidency through the Muslim Brotherhood, an 85-year-old movement whose members long suffered from repression and arrests, including under dictator Hosni Mubarak until he was ousted in 2011.
Morsi's backers now are crying military coup and Brotherhood spokesman Gehad El-Haddad said the events signify old regime retaliation.
"It is difficult to see something healthy coming out of this in the short term," the International Crisis Group said in a statement Wednesday.
"[This is] a blow to Egypt's fragile democracy, regardless of what one thinks of [Morsi's] presidency, entrenching the view, for some, that mass protests backed by the army can trump the ballot box, and, in other quarters, that investing in a peaceful democratic process is simply not worthwhile," the statement said.
A priority now should be trying to avoid bloodshed, the group said.
At least 10 people died overnight and over 400 were injured, according to reports, in clashes that erupted in pockets across the country between opponents and supporters of Morsi.
Almost 50 people in total have been killed in clashes since Sunday.
"I think the next thing is how to prepare," said opposition figure Mohamed Abou El Ghar, who is part of the coalition that developed the transition plan.
"We will have first a presidential election, or we will have the constitution first - changing items in the constitution," he said.
Precisely when a fresh presidential election will be held is not clear, but many of Morsi's opponents in Tahrir Square Wednesday did not seem concerned about who specifically will rule in the long term.
"I want a new president, but not someone from the Brotherhood," said Roudina Ahmed, 20. She said she would be fine with Mohamed ElBaradei running the country, or Ahmed Shafiq, who ran in the election last year against Morsi.
The new phase of disorder in what has proved to be a turbulent two and a half years since Mubarak was ousted from power escalated earlier this week when protesters, who had mobilized for months, took to squares and streets nationwide calling for Morsi to step down and demanding an early presidential election.
Egypt's army gave politicians a 48-hour ultimatum to resolve the crisis on Monday. But Morsi held firm to his post, repeating in a speech that he would protect his "constitutional legitimacy."
As the deadline Wednesday crept closer, ElBaradei, head of the National Salvation Front, which is the main coalition of opposition groups, met with army chief Abdel Fattah Al-Sisi in a meeting that the Grand Sheikh of Al-Azhar and the head of the Coptic church also attended.
Hours later, the army announced its plan, leaving the nation - and the world - divided over whether the military's move was a coup, or should be hailed as a democratic success resulting from the will of the people.
President Obama on Wednesday ordered that U.S. assistance to Egypt, which totals $1.6 billion annually, be reviewed.
"We are deeply concerned by the decision of the Egyptian Armed Forces to remove President Morsi and suspend the Egyptian constitution," Obama said in a statement.
He called on the Egyptian military to move quickly and responsibly in returning full authority back to a democratically elected civilian government through an inclusive and transparent process. He also urged that arbitrary arrests of Morsi supporters be avoided.
"The United States is monitoring the very fluid situation in Egypt, and we believe that ultimately the future of Egypt can only be determined by the Egyptian people," Obama said.