In a cordial beginning to their transfer of power, US president Barack Obama and President-elect Donald Trump have met at the White House.
Mr Obama called the 90-minute meeting "excellent", and his successor said he looked forward to receiving the outgoing president's "counsel".
At the close of the Oval Office sit-down, Mr Obama said to Mr Trump: "We now are going to want to do everything we can to help you succeed, because if you succeed the country succeeds."
The two men, who have been harshly critical of each other for years, were meeting for the first time, Mr Trump said.
The Republican called Mr Obama a "very good man" and said he looked forward "to dealing with the president in the future, including counsel".
Mr Obama blasted Mr Trump throughout the campaign as unfit to serve as a commander in chief.
Mr Trump spent years challenging the legitimacy of Mr Obama's presidency, falsely suggesting the latter may have been born outside the United States.
But at least publicly, the two men appeared to put aside their animosity.
As the meeting concluded and journalists scrambled out of the Oval Office, Mr Obama smiled at his successor and explained the unfolding scene.
If Mr Trump makes good on his campaign promises, he will wipe away much of what Mr Obama has done during his eight years in office.
The Republican president-elect, who will govern with Congress fully under his party's control, has vowed to repeal Mr Obama's signature healthcare law and dismantle the landmark nuclear accord with Iran.
First lady Michelle Obama also met privately in the White House residence with Mr Trump's wife, Melania, while vice president Joe Biden prepared to see vice president-elect Mike Pence later.
Mr Obama and Mr Trump met alone, without any staff present, White House press secretary Josh Earnest told reporters afterwards.
"The two men did not relitigate their differences in the Oval Office," Mr Earnest said.
"We're on to the next phase."
Mr Trump travelled to Washington from New York on his private jet, breaking with protocol by not bringing journalists in his motorcade or on his plane to document his historic visit to the White House.
He was harshly critical of the media during his campaign and for a time banned news organisations whose coverage he disliked from his events.
From the White House, Trump headed to Capitol Hill for meetings with House Speaker Paul Ryan and Senate Majority Leader Mitch McConnell to discuss the party's legislative agenda.
Mr Ryan, who holds the most powerful post in Congress, was a sometime critic of Mr Trump, was slow to endorse him and did not campaign with the nominee. Mr Pence intended to join both meetings.
As scores of journalists waited to be admitted to the Oval Office to see Mr Obama and Mr Trump together, they saw White House chief of staff Denis McDonough walking along the South Lawn driveway with Jared Kushner, Mr Trump's son-in-law. A handful of Trump aides trailed them.
The anticipated show of civility at 1600 Pennsylvania Avenue contrasted with post-election scenes of protests across a politically divided country.
Demonstrators from New England to the heartland and the West Coast vented against the election winner on Wednesday, chanting "Not my president", burning a papier-mache Trump head, beating a Trump pinata and carrying signs that said "Impeach Trump".
Republicans were emboldened by Mr Trump's stunning victory over Hillary Clinton, giving the party control of the White House and both chambers of Congress.
"He just earned a mandate," Mr Ryan said.
In an emotional concession speech, Mrs Clinton said her crushing loss was "painful and it will be for a long time" and acknowledged that the nation was "more divided than we thought".
Still, Mrs Clinton was gracious in defeat, declaring: "Donald Trump is going to be our president. We owe him an open mind and the chance to lead."
In Washington, Mr Trump's scant transition team sprang into action, culling through personnel lists for top jobs and working through handover plans for government agencies.
A person familiar with the transition operations said the personnel process was still in its early stages, but Mr Trump's team was putting a premium on quickly filling key national security posts.
According to an organisational chart for the transition obtained by the Associated Press, Mr Trump was relying on experienced hands to help form his administration.
National security planning was being led by former Michigan Representative Mike Rogers, who previously worked for the FBI. Domestic issues were being handled by Ken Blackwell, a former Cincinnati mayor and Ohio secretary of state.
Mr Trump was expected to consider several loyal supporters for top jobs, including former New York mayor Rudy Giuliani for attorney general or national security adviser and campaign finance chairman Steve Mnuchin for Treasury secretary.
Former House speaker Newt Gingrich and Tennessee senator Bob Corker were also expected to be under consideration for foreign policy posts.
As president-elect, Mr Trump is entitled to get the same daily intelligence briefing as Mr Obama - one that includes information on US covert operations, information gleaned about world leaders and other data gathered by America's 17 intelligence agencies.
The White House said it would organise two exercises involving multiple agencies to help Mr Trump's team learn how to respond to major domestic incidents.