Mohamed Morsi took the oath of office on Saturday to become Egypt's first Islamist president and its first elected head of state since the revolt that overthrew Hosni Mubarak overthrow last year.
The ceremony took place in the constitutional court rather than parliament, the result of an ongoing tussle with the military that took charge after Mubarak's overthrow and insists on retaining broad powers now.
"I swear by the Almighty God to sincerely preserve the republican order and to respect the constitution and law, and completely care for the people's interest," he said at the ceremony at the court.
Morsi had wanted to take the oath before parliament, but the military has disbanded the Islamist-dominated house following a court order.
In an address at Cairo University following his swearing-in, Morsi thanked the military for seeing through the presidential elections but pointedly mentioned the "elected parliament" several times.
"The elected institutions will return to fulfilling their roles. And the great military will devote itself to the task of protecting the country," he told his audience, which included the military's leader, Field Marshal Hussein Tantawi.
He then set out some of his international and domestic objectives, saying he would be a "servant of the people" in a "democractic, modern and constitutional state".
Internationally, he said Egypt respected would back the Palestinians and called for an end to the bloodshed in Syria.
"I announce from here that Egypt, its people and presidential institution stand with the Palestinian people until they regain all their rights," he said.
"We support the Syrian people. We want the bloodshed to stop," he added.
He repeated that Egypt would respect its international treaties, in an allusion to its 1979 peace accord with Israel.
"We carry a message of peace to the world, accompanied and preceded by a message of right and justice."
Morsi, who resigned from the Muslim Brotherhood after winning the election this month, had spoken out forcefully in support of Palestinians during his campaign.
The Brotherhood is vehemently opposed to Syrian president Bashar al-Asad and supports the uprising against him.
But as president, Morsi is not expected to radically change his country's foreign policy, especially towards Israel, in which the military is expected to exercise its clout.
In a Friday speech before tens of thousands of supporters in Cairo's Tahrir Square, the epicentre of the revolt that ousted Mubarak, he said that he would insist on retaining all the presidency's powers.
"I renounce none of the prerogatives of president," he said.. "You are the source of power and legitimacy," he told his supporters.
"There is no place for anyone or any institution ... above this will."
The Supreme Council of the Armed Forces (SCAF) assumed parliament's powers after disbanding it and also formed a powerful national security council headed by the president but dominated by the generals.
The military also reserves the right to appoint a new constituent assembly should the one elected by parliament be disbanded by a court decision expected on September 1.
The Muslim Brotherhood insists that only parliament can appoint the assembly.
Media reports said Morsi was consulting a cross-section of Egyptian society before appointing a premier and a cabinet made up mostly of technocrats.
In a meeting with newspaper editors reported by most dailies on Friday, he pledged there would be "no Islamisation of state institutions" during his presidency.
Morsi has already met SCAF head Field Marshal Hussein Tantawi, as well as a delegation from the Sunni body Al-Azhar and another representing Egypt's Coptic church.
International Monetary Fund chief Christine Lagarde has told him the lender stands ready to help Egypt, whose tourism-dependent economy took a battering in the upheaval that accompanied and followed Mubarak's overthrow, a spokeswoman said on Friday.
Morsi became the Brotherhood's candidate to succeed Mubarak only after its first choice, Khairat El-Shater, was disqualified. He beat Ahmed Shafiq, Mubarak's last premier, with 51.73 percent of the vote.
Many had written him off as an uncharismatic substitute, saying he would be unable to muster widespread support.
But the powerful Brotherhood mobilised its formidable resources and supporters behind Morsi, who was appointed last year to head its political arm, the Freedom and Justice Party.
In a 2005 election, which gave the Brotherhood one fifth of the seats in parliament, Morsi kept his seat. But he was soon arrested and jailed for seven months after taking part in protests supporting reformist judges.
By the 2010 election, Morsi had become a spokesman for the Islamists and a member of their politburo.