US President-elect Donald Trump has signalled he is ready to move swiftly to dismantle Barack Obama's signature healthcare reforms when he takes office in the new year.
The two men met for the first time on Thursday in the Oval Office for talks aimed at delivering a smooth transition of power after Mr Obama leaves the White House for the final time in January.
Afterwards they both struck a notably respectful tone when they faced reporters in sharp contrast to the bitterness and acrimony of the election campaign.
Later, however, following talks with congressional leaders, Mr Trump - who has pledged to repeal so-called "Obamacare" - said healthcare would be among his top priorities in office.
The president-elect - who has also said he intends to build a wall between the United States and Mexico – said he would also be taking early action on immigration, but gave no further details.
"We're going to move very strongly on immigration. We will move very strongly on healthcare. And we're looking at jobs. Big league jobs," he said.
The discussion between Mr Trump and Mr Obama - originally scheduled for no more than 15 minutes - lasted for almost an hour and a half.
Mr Trump said their talks had been wide-ranging, with the president explaining "some of the difficulties" the country faced but also "some of the really great things that have been achieved".
Mr Obama in turn said he was "encouraged" by Mr Trump's willingness to work with his team, telling him: "We want to do everything we can to help you succeed because if you succeed the country succeeds."
Earlier Mr Trump spoke with Theresa May for the first time since his stunning victory, inviting the Prime Minister to visit him in Washington "as soon as possible" after his inauguration on January 20.
The call only came, however, after Mr Trump had first spoken to a series of other world leaders including Ireland's Enda Kenny.
Ministers played down the delay, insisting the "special relationship" between the US and the UK remained intact.
A No 10 spokesman said Mr Trump had set out his "close and personal connections with, and warmth for, the UK" and expressed confidence the special relationship would go "from strength to strength".
Mrs May had then referred to the two countries' "long history of shared values" saying they had "always stood together as close allies when it counts the most".
The spokesman said: "President-elect Trump strongly agreed and added that the UK is a 'very, very special place for me and for our country'."
Foreign Secretary Boris Johnson also spoke to Vice President-elect Mike Pence. He said: "We agreed on the importance of the special relationship and the need to tackle global challenges together."
Former cabinet minister Iain Duncan Smith said the election of Mr Trump should be seen as an "opportunity" for the UK.
"He is well-disposed towards the UK. We've had a very poor special relationship with President Obama. It has been pretty much in the freezer now for about eight years," he told BBC2's Newsnight.
"I think there is a real opportunity for us now with Donald Trump there for us to be able to reinvigorate that relationship."
Earlier Chancellor Philip Hammond played down Mr Trump's anti-global trade stance during the election campaign, amid fears it could tip the world into recession.
"The president-elect has only been the president-elect for two days," Mr Hammond said. "I think we should let him take stock and sit with his advisers and consult widely. Then of course we will look forward to engaging with him."