Obama raring to go as inauguration looms

Barack Obama's team vowed on Sunday to hit the ground running on the recession-hit economy and Iraq as a star-studded concert kicked off a three-day inauguration party for America's first black president.

In advance of the concert headlined by U2 and Bruce Springsteen, Obama struck a more sombre note as he joined vice president-elect Joseph Biden in laying a wreath at the Tomb of the Unknown Soldier in Arlington Cemetery.

Dressed in black winter coats to guard against Washington's arctic chill, Obama and Biden held their hands over their hearts as Taps, the US military's haunting lament to the fallen, was played by a lone bugler.

Obama and his wife Michelle then climbed into the incoming president's new armoured Cadillac with a blue licence plate reading "44" - his numerical position as the newest, and first African-American, commander-in-chief.

Hollywood royalty including Tom Hanks, Jamie Foxx and Denzel Washington were to recite historical passages interspersed with the all-star musical lineup at Sunday's concert in front of the Lincoln Memorial.

Tens of thousands were attending the event, the advance guard of an inaugural crowd expected to number millions, as an unprecedented security operation began with police and army reservists taking up position across the capital.

With the build-up to Tuesday's momentous inauguration gathering pace, Obama and Biden arrived in Washington late on Saturday after a day-long train ride past thousands of well-wishers braving the icy cold in the US northeast.

"Let's make sure this election is not the end of what we do to change America, but the beginning," the president-elect said as he trundled towards the US capital and his place in history.

Along a railroad from Philadelphia to Washington, a route once traced by his hero, Civil War president Abraham Lincoln, Obama urged Americans to adopt a new declaration of independence from bigotry, small thinking and ideology.

Aides said those themes will figure large in Obama's inaugural address after he is sworn in at noon on Tuesday and takes his place alongside the pantheon of past presidents including Lincoln and Franklin D Roosevelt.

Rahm Emanuel, the next White House chief of staff, told NBC the speech would declare an end to "the culture of anything goes" and demand a new era of responsibility from government, corporate boardrooms and the American people.

Polls showed Obama will enter the White House with the highest ratings of any president since Republican icon Ronald Reagan in 1981 - and expectations of a seachange for the world's most powerful nation are sky high.

Incoming White House press secretary Robert Gibbs vied to temper those expectations, which are intense worldwide as well as at home as the US grapples with its longest recession since World War II.

"We did not get into the situation overnight. The problems and the challenges that our country face didn't happen all last week. It's going to take us some time," Gibbs said on Fox News Sunday.

But Gibbs and other senior aides said Obama would lose no time in enacting his economic revival plans through a mammoth stimulus package worth more than $US800 billion ($A1.2 trillion).

And on his first day in office, the aides said, Obama will also convene his top military brass to map a way out of Iraq and recommit US troops against a resurgent Taliban in Afghanistan.

"He will be meeting with the Joint Chiefs of Staff to begin an orderly and responsible withdrawal from Iraq," senior adviser David Axelrod told CNN.

President George W Bush's successor will also quickly get down to work on the Middle East, and hopes a ceasefire between Israel and Gaza militants will endure, Axelrod said.

"Let me say that all of us are hopeful that a cessation of violence will hold," he said as Palestinian militants announced a one-week ceasefire on Sunday after Israel called a unilateral halt to its massive offensive on Gaza.

Asked if Obama would immediately name a special envoy for the Middle East peace process, Axelrod stressed that Obama "intends to engage early and aggressively with diplomacy all over the world."