Amid a huge crowd gathered in the cold in Washington, Barack Hussein Obama was sworn in as the 44th President of the United States of America, calling the country to usher in a new era of responsibility facing the stiff challenges of a faltering economy, wars in the middle east, and a faltering national confidence.

Obama stood before Chief Justice John Roberts, his hand raise and pledged to faithfully execute his office, shaking hands with well wishers gathered around him.

Military canons fired in the distance as the crowd waved its hands and roared in their approval as Obama took in the scene and waved back, before resuming his place at the podium to address the nation in his first speech as the government's Chief Executive.

His speech focused on the difficulties the nation is facing, alluding to them as gathering clouds and raging storms.

He said the country is experiencing a sapping of confidence and nagging fear that America's decline is inevitable, and that the next generation must lower its sights.

They will not be met easily or in a short span of time. But know this, America - they will be met. On this day, we gather because we have chosen hope over fear, unity of purpose over conflict and discord, he said.

With 11 million Americans out of work and trillions of dollars lost in the stock market's tumble, Obama emphasized the need for hard work to overcome the challenges the nation faces. When speaking about work to be done, he mentioned the economy first, alluding to government programs already being considered. Obama's predecessor George Bush, in attendance for the ceremony, leaves office amid a weakened economy, having begun some of the federal initiatives to restore the financial system.

The President stood opposite the Lincoln Memorial, two miles away, where 45 years ago, Martin Luther King Jr. called upon the nation to judge people by the content of their character, not the color of their skin.

Mr. Obama spent Monday celebrating Dr. King's birthday as a day of service, while street vendors sold memorabilia juxtaposing the images of the two black leaders.

Earlier Tuesday, Mr. Obama and his family attended a private service at St. John's Episcopal Church, a tradition for those about to become president. The family of Vice President-elect Joe Biden also attended. The Obamas waved to bystanders, then entered the church to applause from about 200 people. The choir and congregation began singing the hymn, O God Our Help in Ages Past.''

Barack obama George W. Bush