White House spokeswoman Dana Perino would only say that domestic and international issues were discussed and that Bush "again pledged a smooth transition."

Obama spokeswoman Stephanie Cutter said the leaders agreed on the need to cooperate in the changeover "in light of the nation's many critical economic and security challenges."

Later, as Obama's plane sat on the airport tarmac in Washington before taking off for Chicago, journalists onboard overheard snippets of a cell phone conversation the president-elect had with an unknown party.

"I am not going to be spending too much time in Washington over the next several weeks," Obama said.

Newly elected presidents traditionally visit the White House between election and inauguration but usually wait longer than Obama did. He came calling at Bush's invitation after only six days, underscoring a sense of urgency in the transition.

It will be the first wartime transfer of power in four decades and comes amid economic upheaval at home and abroad.

Financial markets, struggling in a global credit crunch, are awaiting news of Obama's appointments for key jobs such as Treasury secretary, but a spokeswoman for Obama said on Monday he would not make any Cabinet announcements this week.

Obama said in his first post-election news conference on Friday he would not be rushed into making hasty decisions.

Underscoring Obama's assertion he will not act as a shadow president during the transition, an aide confirmed what the White House had been saying -- that he will not attend a global financial summit in Washington on Friday and Saturday.

... contd.