Top Democrat Nancy Pelosi has warned “hundreds of thousands” of Americans will die if congressional Republicans pass their healthcare legislation.

President Donald Trump’s party is struggling to secure the votes to get its bill through the Senate.

Republican Senator Ron Johnson said on Sunday there should “no way” be a vote on the legislation this week.

At least five Republicans are opposed to their party’s bill, which can only afford to lose two votes.

The Senate bill would slash taxes for the wealthy while imposing cuts on Medicaid, a healthcare programme for the poor, and offer less help for working families to buy medical insurance.

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House of Representatives minority leader Nancy Pelosi told CBS This Morning on Monday: “We do know that many more people – millions, hundreds of thousands – of people will die if this bill passes.

“These bills systemically, structurally, they are very, very harmful to the American people.

“They will raise costs with fewer benefits, have an age tax, they will undermine Medicare.”

Republicans are expected to issue a revised version of their bill on Monday, a Senate aide told Reuters news agency, without detailing the revisions.

‘Reduced to a budget line’

Away from the policy debate on Capitol Hill, a New Jersey mother’s viral tweet has put a human face on the US healthcare debate.

Alison Chandra posted a photo of a medical bill for her son, Ethan, who was born with a rare genetic disorder, heterotaxy syndrome.

Ms Chandra tweeted: “Without insurance we would owe $231,115 for 10 hours in the OR [operating room], 1 week in the CICU [cardiac unit] and 1 week on the cardiac floor.”

She says she is worried because the Republican legislation does not cover essential health benefits, including the prescription medications that her son will rely on for the rest of his life.

“It seems like our kids are being reduced to a line in a budget,” she told CNN. “No one seems to realise there are real people behind it.”

With not a single Democrat supporting the bill, Republicans face some legislative arm-twisting to rally their rank and file.

But Wisconsin’s Ron Johnson has moved to put the brakes on the party leadership’s plan to hold a vote this week.

“We don’t have the courage in Washington, the honesty, to talk about this issue with real facts,” he told NBC’s Meet the Press on Sunday. “There’s no way we should be voting on it this next week, no way.”

He is one of four hardline conservative senators who think the Senate bill does not do enough to lower health costs. The others are Ted Cruz of Texas, Rand Paul of Kentucky and Mike Lee of Utah.

On Friday, Nevada Senator Dean Heller became the fifth Republican senator to publicly come out against the legislation.

He said the party leadership’s claim that the bill would lower health costs is “a lie”.

A political action committee has threatened to launch attack ads to pressure Mr Heller into supporting the legislation.

Also on Sunday, Louisiana Senator Bill Cassidy declared himself “undecided”, saying the bill contains provisions “which adversely affect my state, that are peculiar to my state”.

Kellyanne Conway, an adviser to Mr Trump, claimed on Sunday the Senate bill would not actually cut Medicaid, despite projections that it would slash $800bn (£630bn) from the programme.

Maine Senator Susan Collins told ABC’s This Week on Sunday she worries about “what [the bill] means to our most vulnerable citizens”.

The president took to Twitter on Monday to attack his political adversaries.

“The Democrats have become nothing but OBSTRUCTIONISTS, they have no policies or ideas,” he tweeted. “All they do is delay and complain. They own ObamaCare!”

But their support is unlikely, given that Republicans are trying to overturn one of the most cherished policy accomplishments of any Democratic administration in decades.

The Senate healthcare bill was crafted in secret with only a small number of Republicans consulted, and no Democrats were asked their opinion.

An opinion poll last week found that for the first time former President Barack Obama’s 2010 Affordable Care Act – known as Obamacare – is now viewed positively by more than half Americans (51%).