US President Donald Trump has demanded a make-or-break Friday vote on a new health care bill in the House of Representatives.

The American Healthcare Act is intended to replace parts of President Barack Obama’s signature law.

But Thursday’s vote was delayed because of opposition from some Republicans – despite Mr Trump’s repeated attempts to persuade them to back the legislature.

He now says he wants to move on and vote – whatever the result on Friday.

White House budget director Mick Mulvaney said this was exactly the message delivered to Republican lawmakers at a meeting behind closed doors on Thursday.

“For seven-and-a-half years we have been promising the American people that we will repeal and replace this broken law because it’s collapsing and it’s failing families, and tomorrow we’re proceeding,” House Speaker Paul Ryan said.

Meanwhile, Chris Collins, New York’s Republican representative, said: “The president has said he wants a vote tomorrow, up or down”.

“If for any reason it is down, we are just going to move forward with additional parts of his agenda.”

Repealing and replacing so-called Obamacare was a major plank of Mr Trump’s election campaign.

Thursday’s vote postponement is a setback for the president who had insisted he would win the numbers to pass it through the lower chamber of Congress on that day.

The problem is that Republicans are unable find a compromise: the current reforms go too far for some and not far enough for others, the BBC’s Laura Bicker in Washington says.

The hope is that Mr Trump’s new strategy will force Republican lawmakers opposed to the bill to vote “yes” – the alternative being that Mr Obama’s health law would be kept in place.

But the outcome is far from assured, our correspondent says.

Earlier on Thursday, House Minority Leader Nancy Pelosi said Mr Trump had made a “rookie’s error for bringing this up on a day when clearly you’re not ready”.

The bill needs 215 votes to pass but ran into opposition mainly from conservative Republicans who believed it did not roll back enough of Mr Obama’s Affordable Care Act.

More on the healthcare story

• What are the Republicans proposing?
• All-male White House health bill photo sparks anger
• Trump health bill: Winners and losers
• Is Obamacare more popular than ever?
• A bumpy 24 hours for Trump health bill

Obamacare helped 20 million previously uninsured Americans get health insurance but has been plagued by increases in insurance premiums, which were also a problem before the health law.

Mr Trump promised a new law that would cover more people and at a lower cost.

The Republican bill keeps some of the popular elements of Obamacare but limits future federal funding for Medicaid, which covers low-income people.

A new estimate by the Congressional Budget Office released on Thursday evening said recent changes to the bill would make it costlier than previously thought.

The number of uninsured Americans would rise to 24 million by 2026 under the new law, the budget analysis said.

Groups representing doctors, hospitals and the elderly have said they are opposed to the Republican bill.

Key elements of the new bill:

• Cuts the Medicaid programme for low earners
• Provides tax credits to help people pay medical bills, but reduced compared to Obamacare
• Ends penalties on those who do not buy health coverage
• Allows insurers to raise premiums for older people
• Blocks federal payments to women’s healthcare provider Planned Parenthood for a year