Four Senate Republicans announced Thursday that they now oppose the health care bill to repeal and replace Obamacare that was released only hours earlier, putting its passage in jeopardy.

Walker, a Republican-turned-independent, made his comments after Republicans in the U.S. Senate released a draft health care bill Thursday.

The bill would end tax penalties on people who don't buy insurance and on large companies that don't offer coverage to employees and would phase out extra federal money that Obamacare provides to states that have expanded Medicaid coverage.

Senate Democratic leaders blasted the Republican Senate health care bill dubbing it as "meaner" than the House version.

President Donald Trump had used the word "mean" to describe the House version of the bill.

Senate Majority Leader Mitch McConnell, R-Kentucky, said he could bring the bill for a floor vote as early as next week, despite concerns some GOP senators have raised on the measure.

America's Essential Hospitals, which represents more than 300 safety-net health facilities, says the version the Senate released Thursday "might be worse overall" than the House legislation and might lead to hospitals reducing services or closing.

Republicans need 50 votes, plus a tie-breaker vote from Vice President Mike Pence, out of the 52 GOP senators, so the threat of losing four votes straight out of the gate doesn't make it easy on the party.

The overall impact the proposal would have on insurance markets in the USA won't really come into focus until the Congressional Budget Office and other experts have the time to assess the various changes it would make to system put in place under the ACA.

Senator Lindsey Graham of SC added: "I think we're probably gonna get a lot of pushback from people from the right in the House".

"Not once have I or my colleagues been asked by a single Republican to work on this bill or discuss bipartisan fixes", said Democratic Sen.

The Senate bill would cap future federal aid to states for Medicaid, fundamentally transforming a safety-net health insurance program that now covers about 70 million poor Americans.

"We have to act", Mr McConnell said on the Senate floor. The Senate bill is largely in line with Obamacare, tying subsidies for people paying for individual coverage to prices where they live and their income.

Cruz, who has a history of creating trouble for GOP leaders, has positioned himself in recent weeks as something of a consensus-builder within the Senate GOP conference on health care. Paul told CNN that he wouldn't vote for anything that looks like the House's AHCA bill.

Later on Thursday, Paul announced that he and three fellow Republican senators would soon announce their opposition to the bill as written.

The nonpartisan Congressional Budget Office estimated the House bill would kick 23 million people off their healthcare plans.

Democrats, including Baldwin, Stabenow and New York Senator Chuck Schumer, all criticized the secret talks among Republicans with no input from Democrats or the public.

But Republicans, struggling to make good on a more than half-decade old pledge to dismantle Obama's signature piece of public policy, are plunging forward nonetheless.

"They're going to have to do something that ... moves the American people in the direction to where health care is going to be made more affordable", Lee said. "So if you're frustrated by the lack of transparency in this process, I share your frustration".

Susan Collins of ME said it was "too soon" to judge the bill and she has some concerns about cuts to Medicaid after 2025 and defunding of Planner Parenthood. But it would shrink the program even more over time by pegging the annual growth rate of those funds to standard inflation, rather than the more generous medical inflation, starting in 2025.

"Medicaid is the program in this country that provides health insurance to one in five Americans, to 30 million kids, to almost two out of every three people in a nursing home", she said.