WASHINGTON (AFP) - - US President George W. Bush on Wednesday publicly congratulated Barack Obama on his historic victory and vowed "complete cooperation" as the first black US president moves into the White House.

"Last night, I had a warm conversation with president-elect Barack Obama. I congratulated him and Senator (Joe) Biden on their impressive victory," Bush said in his first public remarks on the election.

"I told the president-elect he can count on complete cooperation from my administration as he makes the transition to the White House," said the outgoing president, whose second four-year term ends January 20.

Bush also said he and First Lady Laura Bush had invited Obama and wife Michelle Obama to come to the presidential mansion, "and Laura and I are looking forward to welcoming them as soon as possible."

Bush, whose vast unpopularity weighed down fellow Republican and chosen successor John McCain's campaign, said he had also spoken to the defeated Arizona senator.

"I congratulated him on a determined campaign that he and Governor Palin ran," he said, referring to Alaska Governor Sarah Palin, who would have been the first woman vice president.

"The American people will always be grateful for the lifetime of service John McCain has devoted to this nation. And I know he'll continue to make tremendous contributions to our country," said Bush.

He also left little doubt about the president-elect's say in charting the nation's course over the next 76 days, saying he would keep Obama "fully informed on important decisions."

But "there's important work to do in the months ahead, and I will continue to conduct the people's business as long as this office remains in my trust," said Bush.

Eight years after campaigning on a pledge to be "a uniter not a divider," Bush was to leave a politically polarized country in which nine out of ten citizens worry the nation is on the wrong course but disagree what to do.

"No matter how they cast their ballots, all Americans can be proud of the history that was made yesterday," said the president, who underlined the historic nature of the choice made at the polls a day earlier.

"Many of our citizens thought they would never live to see that day. This moment is especially uplifting for a generation of Americans who witnessed the struggle for civil rights with their own eyes -- and four decades later see dream fulfilled," he said.

"A long campaign has now ended, and we move forward as one nation. We're embarking on a period of change in Washington, yet there are some things that will not change," he said.

"The United States government will stay vigilant in meeting its most important responsibility -- protecting the American people. And the world can be certain this commitment will remain steadfast under our next Commander-in-Chief," Bush said in his three-minute statement.

"And when the time comes on January the 20th, Laura and I will return home to Texas with treasured memories of our time here -- and with profound gratitude for the honor of serving this amazing country."