By Asma Alsharif and Shadia Nasralla
CAIRO (Reuters) - Egyptian security forces arrested the leader of the Muslim Brotherhood on Thursday, security sources said, in a crackdown against the Islamist movement after the army ousted the country's first democratically elected president.
The dramatic exit of President Mohamed Mursi was greeted with delight by millions of jubilant people on the streets of Cairo and other cities overnight, but there was simmering resentment among Egyptians who opposed military intervention.
An Islamist coalition led by the Brotherhood called on people across the nation to protest in a "Friday of Rejection" following weekly prayers, an early test of Mursi's ongoing support and how the military will deal with it.
Perhaps aware of the risk of society being polarized, the new interim leader, judge Adli Mansour, used his inauguration to hold out an olive branch to the Brotherhood, Mursi's power base.
"The Muslim Brotherhood are part of this people and are invited to participate in building the nation as nobody will be excluded, and if they respond to the invitation, they will be welcomed," he said.
Just before he spoke, the air force staged a series of fly pasts in the smoggy skies over Cairo, a stark reminder of the military's role in the latest upheaval. The stunt, involving dozens of aircraft, was repeated at dusk.
But a senior Brotherhood official said it would not work with "the usurper authorities". Another of its politicians said Mursi's overthrow would push other groups, though not his own, to violent resistance.
Mursi's removal after a year in office marked another twist in the turmoil that has gripped the Arab world's most populous country in the two years since the fall of Hosni Mubarak.
At least 16 people have been killed and hundreds wounded in clashes across Egypt since Mursi's overthrow. In fighting late on Thursday between his supporters and opponents in his hometown of Zagazig northeast of Cairo, 80 more people were wounded.
According to state news agency MENA, protesters fought with rocks, birdshot and knives, and security forces fired teargas to disperse them and made 11 arrests.
INVESTIGATION OPENED INTO MURSI
The United Nations, the United States and some other world powers avoided condemning Mursi's removal as a military coup. To do so might trigger sanctions.
Army intervention was backed by millions of Egyptians, including liberal leaders and religious figures who expect new elections under a revised set of rules.
Egypt's armed forces have been at the heart of power since officers staged the 1952 overthrow of King Farouk.
The protests that spurred the military to step in this time were rooted in a liberal opposition that lost elections to Islamists. Their ranks were swelled by anger over broken promises on the economy and shrinking real incomes.
The downfall of Egypt's first elected leader, who emerged from the "Arab Spring" revolutions that swept the region in 2011, raised questions about the future of political Islam which only lately seemed triumphant.
Deeply divided, Egypt's 84 million people are again a focus of concern in a region traumatized by the civil war in Syria.
Security sources said the Muslim Brotherhood's supreme guide, Mohamed Badie, was arrested in the northern city of Marsa Matrouh, near the Libyan border, although the sources said they did not believe he had been trying to flee the country.
The Brotherhood denied his arrest on its website.
Demonstrators often chanted against Mursi and Badie in the same breath. Despite its denials, the Brotherhood never managed to shake off the image that Badie and its executive board were the silent force behind Mursi's presidency.
Prosecutors also ordered the arrest of his influential deputy Khairat el-Shater after both men were charged with inciting violence against protesters outside the Brotherhood's headquarters in Cairo that was attacked on Sunday night.
Mursi was in military custody, army and Brotherhood sources said, and authorities opened an investigation into accusations that he and 15 other Islamists insulted the judiciary.
A senior Brotherhood politician, Essam El-Erian, said the movement would take a long view of the political setback, and that Egypt's Islamist leaders had not been given a fair chance to succeed in office.
Mohamed El-Beltagy, another senior Brotherhood politician, said the movement would not take up arms over what he called a military coup, although he warned that other, unnamed, groups could be pushed to violent resistance by recent events.
There was also a call from calm from the influential Dawa Salafiya movement of Egyptian Salafists, ultra-orthodox Islamists who have occasionally been allied with Mursi but distanced themselves from him in recent weeks.
"IT'S ABOUT EGYPT"
Outside the court where Mansour was sworn in, 25-year-old engineer Maysar El-Tawtansy summed up the mood among those who voted for Mursi in 2012 and opposed military intervention.
"We queued for hours at the election, and now our votes are void," he said. "It's not about the Brotherhood, it's about Egypt."
For the defeated Islamists, the clampdown revived memories of their suffering under the old, military-backed regime led by Mubarak, himself toppled by a popular uprising in 2011.
The clock started ticking for Mursi when millions took to the streets on Sunday to demand he resign. They accused the Brotherhood of hijacking the revolution, entrenching its power and failing to revive the economy.
That gave armed forces chief General Abdel Fattah al-Sisi, who already had his own reservations about the state of the nation under Mursi, a justification to invoke the "will of the people" and demand the president share power or step aside.
The United States and other Western allies had also pressed Mursi hard to open his administration to a broader mix of ideas.
Sisi, in uniform and flanked by politicians, officers and clergy, called on Wednesday for measures to wipe clear a slate of messy democratic reforms enacted since Mubarak fell. The constitution was suspended.
A technocratic interim government will be formed, along with a panel for national reconciliation, and the constitution will be reviewed. Mansour said fresh parliamentary and presidential elections would be held, but he did not specify when.
Liberal chief negotiator Mohamed ElBaradei, a former U.N. nuclear agency chief and favorite to become prime minister in the interim government, said the plan would "continue the revolution" of 2011.
Foreign Minister Mohamed Kamel Amr said he had assured U.S. Secretary of State John Kerry in a telephone call on Thursday that Mursi's overthrow was not a military coup.
"This was actually the overwhelming will of the people," Amr told Reuters. Amr tendered his resignation on Tuesday but remains in office in a caretaker capacity.
U.S. President Barack Obama, whose administration provides $1.3 billion a year to the Egyptian military, expressed concern about Mursi's removal and called for a swift return to a democratically elected civilian government.
But he stopped short of condemning the military move in a way that might block U.S. aid. A senator involved in aid decisions said the United States would cut off its financial support if the intervention was deemed a military coup.
Israel avoided any show of satisfaction over the fall of an Islamist president. Many in the Jewish state had been initially alarmed by Mursi's rise although early in his term Mursi made clear he would not renege on a 1979 peace treaty with Israel.
The new emir in Qatar, which has provided billions of dollars in aid to Egypt following the ousting of Mubarak, congratulated Mansour on his appointment.
The markets reacted positively to Mursi's exit. Egypt's main stock index rose 7.3 percent on the day.
(Reporting by Asma Alsharif, Mike Collett-White, Alexander Dziadosz, Shaimaa Fayed, Maggie Fick, Alastair Macdonald, Shadia Nasralla, Tom Perry, Yasmine Saleh, Paul Taylor, and Patrick Werr in Cairo, Abdelrahman Youssef in Alexandria and Yursi Mohamed in Ismailia, Michelle Martin in Berlin, Adrian Croft in Brussels, Ayla Jean Yackley in Istanbul, Jeffrey Heller in Jerusalem and Amena Bakr in Dubai; Writing by Mike Collett-White; Editing by Peter Graff)