President Barack Obama has said that United States would support democracy in Africa and elsewhere because it is in its interests to do so.
In his inaugural address delivered Monday shortly after his public oath-taking ceremony in Washington DC, Obama said: "We will support democracy from Asia to Africa; from the Americas to the Middle East, because our interests and our conscience compel us to act on behalf of those who long for freedom."
He also said that America would remain the anchor of strong alliances in every corner of the globe and renew those institutions that extend its capacity to manage crisis abroad, adding, "For no one has a greater stake in a peaceful world than its most powerful nation."
The colourful ceremony watched by millions of people around the world and witnessed by hundreds of thousands of people at the inauguration ground, including two of Obama's predecessors, Jimmy Carter and Bill Clinton, along with their spouses, was themed: "Faith in America's Future".
The first family, Vice-President Joe Biden and his wife had earlier attended a church service at St. John's Episcopal Church before returning to the White House for a brief rest and then headed to Capitol Hill at about 10.35 am for the inauguration ceremony.
Along the routes from the White House to the inaugural ground at Capitol Hill, thousands of people lined up behind law enforcement tapes waving at the presidential convoy as it made its way to the inauguration ground.
Reassuring his nation of the commitment of his administration to their security, Obama said: "We will defend our people and uphold our values through strength of arms and rule of law. We will show the courage to try and resolve our differences with other nations peacefully - not because we are naïve about the dangers we face, but because engagement can more durably lift suspicion and fear."
His inaugural address made before a sea of heads, who waved thousands of star-studded flags, also rekindled hope for immigrants, women, as well as gays as it linked the challenges they face with the journey the United States must embark upon.
He said: "For our journey is not complete until our wives, our mothers, and daughters can earn a living equal to their efforts. Our journey is not complete until our gay brothers and sisters are treated like anyone else under the law - for if we are truly created equal, then surely the love we commit to one another must be equal as well.
"Our journey is not complete until no citizen is forced to wait for hours to exercise the right to vote. Our journey is not complete until we find a better way to welcome the striving, hopeful immigrants who still see America as a land of opportunity; until bright young students and engineers are enlisted in our workforce rather than expelled from our country.
"Our journey is not complete until all our children, from the streets of Detroit to the hills of Appalachia to the quiet lanes of Newtown, know that they are cared for, and cherished, and always safe from harm."
On the importance of the inaugural ceremony, Obama said: "Each time we gather to inaugurate a president, we bear witness to the enduring strength of our constitution.
"We affirm the promise of our democracy. We recall that what binds this nation together is not the colours of our skin or the tenets of our faith or the origins of our names. What makes us exceptional - what makes us American - is our allegiance to an idea, articulated in a declaration made more than two centuries ago."
Delivering the opening remarks at the 57th inaugural ceremony, New York Democrat and head of the congressional committee on inauguration, Senator Chuck Schummer, described the occasion as "the perfect moment to renew our collective faith in America."
The swearing-in of Vice-President Biden by Supreme Court Associate Justice Sonia Sotomayor at about 11.46 am was preceded by the rendering of the "Battle Hymn of the Republic" by the famous Brooklyn Tabernacle choir.
Adding colour to the ceremony were Singer Kelly Clarkson, who performed "America (My Country 'Tis of Thee)", singer James Taylor, who performed "America the Beautiful", Beyonce, who performed the national anthem, Richard Blanco, who gave the inaugural poem, and the US Marine Band.
The first official assignment performed by Obama after his inauguration was the signing of the paperwork to nominate four new members of his cabinet and national security team - John Brennan, CIA; Chuck Hagel, Secretary of Defence; John Kerry, Secretary of State; and Jack Lew, Secretary of the Treasury.
Two official balls - the Commander-in-Chief's Ball - for members of the armed services, and the inaugural ball, for the invitees of the president, also held Monday.
The inaugural ceremonies would be round off Tuesday with a national prayer service at the National Cathedral also in Washington DC.