The new Republican health insurance bill is facing opposition from some of its own senators in the lead-up to a vote to approve it later this week.

The 142-page proposal, drafted mainly by the Senate majority leader Mitch McConnell, was unveiled on Thursday.

It aims to deliver on a central campaign promise of President Donald Trump to undo former President Barack Obama's signature health insurance law, which has provided coverage to 20 million Americans since it was passed in 2010.

Republicans view the law, formally known as the Affordable Care Act, as a costly government intrusion and say individual insurance markets created by it are collapsing.

Sanders' criticism

Democrat Senator Bernie Sanders has criticised the proposed bill and said that lives were at stake if it passes.

"When you throw over 23 million people off of health insurance, thousands of people will die," he said.

Senate Democrats are not expected to back it, which means McConnell cannot afford to lose more than two Senate Republicans.

However, five Senate Republicans have publicly voiced their opposition to the current Senate draft, while others have expressed concern.

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Supporters of the bill say that it promises to end the requirement that all Americans get health coverage or else pay a penalty.

Yet others have expressed concern over the content of the bill and the ramifications it could have for their constituents.

A number of Republican governors have joined doctors, hospitals and patient advocacy groups in opposing the bill, in part because of its cuts to federal Medicaid funding that covers more than 70 million poor Americans.

Governors now face the challenge of deciding whether to reduce medical services, limit who can enrol in a health insurance safety net, or make cuts to other state programmes such as education or transportation.

Call for slowdown

Ron Johnson of Wisconsin, one of the Republican senators who oppose the bill, called for a slowdown in the process to give the Senate and the public time to evaluate the health insurance bill.

"We don't have enough information. I don't have the feedback from constituencies who will not have had enough time to view the Senate bill. We should not be voting on this next week," he told NBC.

The other senators who do not support the bill are Dean Heller of Nevada, Rand Paul of Kentucky, Ted Cruz of Texas and Mike Lee of Utah.

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Senator Susan Collins of Maine, a moderate Republican who has not taken a formal stance on the bill, expressed her concern that cuts to Medicaid would affect it deeply.

"I have very serious concerns about the bill," she said on ABC's This Week programme. "It's hard for me to see the bill passing this week."

The bill is supported by Trump. In a Sunday interview on Fox News, Trump said: "Healthcare is a very, very tough thing to get. But I think we’re going to get it. We don’t have too much of a choice because the alternative is the dead carcass of Obamacare."

Source: Al Jazeera and news agencies