In the past 48 hours, he has moved swiftly to shape his new administration, scheduled his first post-election visit to the White House, met officials for his first classified intelligence briefing and prepared for a weekend meeting of his economic advisory team and a press conference after that.

With more bad news on the economic front and two wars going on in Iraq and Afghanistan, the sense of urgency was palpable in both the Bush administration and the incoming Obama team.

'We face economic challenges that will not pause to let a new president settle in,' said President George W. Bush on Thursday. 'This will also be America's first wartime transition in four decades.'

The White House is especially concerned that the country will be vulnerable to terrorist attacks during the transition phase.

In one sign of that, Mr Mike McConnell, the director of national intelligence, flew to Chicago to present Mr Obama with his first top-secret intelligence briefing on Thursday.

'We're in a struggle against violent extremists determined to attack us, and they would like nothing more than to exploit this period of change to harm the American people,' Mr Bush told aides at the White House.

'For the next 75 days, all of us must ensure that the next president and his team can hit the ground running.'

The Bush-Obama transition is the first since the terror attacks of Sept 11, 2001, and much of the work is being conducted with an eye towards national security.

At the Department of Homeland Security, for instance, Ms Elaine Duke, an undersecretary, is developing a 'transition and succession plan' to be delivered to the Obama team by Dec 1, as required by a 2007 law.

'We know that terrorists perceive government transitions to be periods of increased vulnerability,' Ms Duke said, citing the bombing of the World Trade Center five weeks after Mr Bill Clinton took office in 1993; the Madrid train bombings in 2004, three days before national elections in Spain; and the car bomb attacks last year in London and Glasgow, just days after a new British prime minister took office.

Moving quickly on his part, Mr Obama has announced his selection of Democrat Congressman Rahm Emanuel as his chief of staff.

Explaining his first appointment, he said Mr Emanuel has 'deep insights into the challenging economic issues that will be front and centre for our administration'.

And even before the inauguration, Mr Obama is already working with Democratic leaders in Congress on plans for two economic-stimulus packages in the next two months.

While Mr Obama is focusing heavily on the economy, advisers say he is also attending to all areas of his administration.

He spent Thursday afternoon making and receiving call after call. In a makeshift office in Chicago, he also spoke to nine world leaders, including President Nicolas Sarkozy of France, Prime Minister Gordon Brown of Britain and Prime Minister Ehud Olmert of Israel.

He is also trying to build his team amid the fevered speculation and jostling that grips Washington during transitions.

Although cooperation with the Democratic-controlled Congress is expected to be smooth, the coordination with the Bush White House is a bit more dicey.

The Obama camp is feeling pressure from the administration, according to several people familiar with the situation, specifically from Treasury Secretary Henry Paulson, to 'co-own' the financial bailout programme, which remains unpopular among voters despite a broad consensus that it was essential to avert wider economic collapse.

Elsewhere, officials are racing to complete budget options for the Obama team, without knowing whether they will be accepted or rejected.

There is little choice; the business of government must go on, and the new administration will be expected to submit a budget to Congress in February, within weeks of Mr Obama's taking office.

Mr Obama, who has declined to attend President Bush's global economic summit on Nov 15, on Thursday accepted an invitation to a meeting at the White House with Mr Bush and First Lady Laura Bush, at what might be the only get-together by the President and his successor before the Jan 20 inauguration.

In a statement, he said: 'Michelle and I look forward to meeting with President Bush and the First Lady on Monday to begin the process of a smooth, effective transition. I thank him for reaching out in the spirit of bipartisanship that will be required to meet the many challenges we face as a nation.'

Mr John Kamensky, a management expert at the IBM Centre for the Business of Government, said he was 'very encouraged' by the progress Mr Obama had made in his first hours as President-elect.

'Obama announced his transition team on Wednesday, not just one person, but a roster of people,' said Mr Kamensky, the co-author of Operator's Manual For The New Administration.

'The most important thing for the new team is to focus on how the White House will operate,' Mr Kamensky said.

'At this stage, it's less important for them to think about specific policy decisions than about the decision-making process - how they will filter the flood of information, who will make decisions, and how.'

LOS ANGELES TIMES, WASHINGTON POST, NEW YORK TIMES