Ex-army chief Abdul Fattah al-Sisi has been sworn in as Egypt's new president after a landslide win in May elections.
He said his election was "a democratic, peaceful handover of power" that represented "a historic moment and turning point" for the nation.
Security forces were deployed at key locations around the capital Cairo for the ceremony at the Supreme Constitutional Court.
The retired field marshal overthrew President Mohammed Morsi last July.
He has since been pursuing a crackdown on Mr Morsi's Muslim Brotherhood, which urged a boycott of the elections.
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The BBC's Orla Guerin in Cairo: Supporters of Abdul Fattah al-Sisi hope there will be ''a new chapter in Egypt's history''
Liberal and secular activists, including the 6 April youth movement which was prominent in the 2011 revolution that ousted long-serving President Hosni Mubarak, also shunned the 26-28 May poll in protest at the curtailing of civil rights.
'No coup'
Mr Sisi, 59, was sworn in for a four-year term at a ceremony shown live on television.
He signed the document authorising him to take over power from interim president, Adly Mansour.
Mr Sisi said: "Throughout its extended history over thousands of years, our country has never witnessed a democratic peaceful handover of power."
He said it was time "for our great people to obtain the fruits of their two revolutions... the time has come to build a more stable future".
Mr Sisi's victory came almost a year after he ousted Egypt's first freely elected president, Mohamed Morsi, following mass protests against his rule.
At the swearing-in, the Supreme Constitutional Court deputy head, Maher Sami, said the ousting was not a coup, and that Mr Sisi had responded to the will of the people.
Justices present for the ceremony applauded after Mr Sisi took the oath.
Mr Sisi vowed he would "establish a new Egypt - a strong, just and secure country which enjoys prosperity".
In the May elections, Mr Sisi secured 96.9% of the vote and his sole challenger, left-winger Hamdeen Sabahi, received only 3.1%. Turnout was less than 50%.
Crowds are expected to flock to Cairo's Tahrir Square to celebrate his victory, the BBC's Orla Guerin in the Egyptian capital reports.
Mr Sisi inherits a nation that is divided and weary, our correspondent says. Experts warn that if he cannot deliver in the next year or two he could also face a mass revolt.
One student, Israa Youssef, told Reuters: "Sisi has to do something in his first 100 days, people will watch closely and there might be another revolution. That's what people are like in this country."
Mohammed Morsi's supporters charged with violence chant slogans against the Egyptian military during a trial. Photo: March 2014
Mr Sisi's opponents fear his election victory will mark a return to authoritarian rule
Mr Sisi faces an array of challenges, including fixing the economy, preventing further political crises and easing poverty.
More than a quarter of Egyptians live below the poverty line. Mr Sisi has pledged to build 26 new tourist resorts, eight new airports and 22 industrial estates.
He has promised to restore security in a country where attacks by Islamist militants have left hundreds of security personnel dead over the past 11 months.
The militants have stepped up attacks in response to the crackdown on the Muslim Brotherhood and its allies, in which more than 1,400 people have been killed and 16,000 detained.
Mr Morsi and other senior leaders of the Brotherhood, which has been designated a terrorist organisation, are standing trial on a series of charges. They strongly deny any wrongdoing.
Critics fear Mr Sisi will continue to show little tolerance for dissent.
Are you in Egypt? What do you think about the election of Abdul Fattah al-Sisi? What should the new president do now? You can send us your comments by emailing haveyoursay@bbc.co.uk using the subject line "Egypt".
