Senate Republican leaders issued a long-awaitedhealth-care proposal aimed at winning over both themoderate and conservative wings of their party, but their draftbill was immediately opposed by a group of four GOP senators.

Related: AHCA continues to bring out thecritics

Senator Rand Paul of Kentucky said he and three otherconservative Republicans -- Ted Cruz of Texas, Ron Johnson ofWisconsin and Mike Lee of Utah -- oppose the version releasedThursday and intend to negotiate as a team to improve it.

Their opposition could threaten passage of the bill. For themeasure to clear the Senate, Republicans can only afford to losetwo GOP votes amid unanimous Democratic opposition.

President Donald Trump offered his strong backing for measure onThursday evening.

“I am very supportive of the Senate #HealthcareBill. Lookforward to making it really special! Remember, ObamaCare is dead,”he wrote on Twitter.

The draft bill includes sharp cuts to Medicaid for the poor anddisabled, more modest trims to other Obamacare subsidies and taxcuts for the wealthy that were included in a version passed by theHouse.

Labeled a "discussion draft," the plan would provide anadditional $50 billion over four years to stabilize insuranceexchanges, relying on a mechanism Republicans have criticized inthe past as a way to keep insurers in the marketplace.

Related: Senate GOP health bill to break with House on keypoints

It largely resembles the House bill passed last month, includingthe tax cuts for wealthy people, drugmakers and insurancecompanies. The Senate bill’s initial Medicaid cuts are moregradual than the House, though both end the open-ended funding ofthe health care system for the poor.

The plan, a product of months of closed-door meetings, includes$15 billion a year in market-stabilizing funds over the next twoyears and $10 billion a year in 2020 and 2021. These payments wouldcome in addition to cost-sharing subsidy payments, which would beextended through 2019.

Related: Trump calls GOP health care bill'mean'

"Perhaps the discussion will begin in earnest to make the billbetter," Paul told reporters. "I think you only get changes if youshow you have the power to, you know, not vote for the currentbill."

Cruz gave flyers to fellow Republicans with his demands: lettingstates design coverage without getting a federal waiver, allowingconsumers to buy insurance across state lines, and allowinginsurers that meet federal mandates to also sell other plans thatdon’t comply.

Senate Majority Leader Mitch McConnell of Kentucky haspreviously said he wants the full chamber to vote on the measurenext week.

Second-ranking Senate Republican John Cornyn of Texas saidleaders want votes on multiple amendments starting June 29, withfinal passage of the bill early the next morning.

The bill will “ultimately transition away from Obamacare’scollapsing system entirely so more Americans won’t be hurt,”McConnell said Thursday on the Senate floor.

Related: Study finds support for ACA provisions --mostly

But holding a vote next week would be potentially risky forRepublican leaders.

"I don’t see how I can get the information I need to get to yesin a week," Johnson told reporters Thursday.

‘Transfer of wealth’

Former President Barack Obama, whose health law was his biggestdomestic achievement, said on Facebook the GOP plan "is not ahealth care bill. It’s a massive transfer of wealth frommiddle-class and poor families to the richest people inAmerica."

Related: ACA bill's burden on poor brings out critics on allsides

Obama urged people to contact their representatives to demandthat lawmakers seek a compromise to improve Obamacare. "Smalltweaks" to the GOP bill "cannot change the fundamental meanness atthe core of this legislation," he said.

Health stocks rose to highs on Thursday, following the bill’srelease. The Standard and Poor’s 500 Health Care Index ofdrugmakers, insurers, hospitals, medical suppliers and other healthcompanies closed at an all-time high, up 1.1 percent.

Hospitals, which would face more gradual cuts to Medicaid underthe Senate bill than the House version, were some of the biggestgainers. Shares of Community Health Systems Inc. closed up 5.1percent to $9.27, while Tenet Healthcare Corp. gained 6.9 percentto $18.90.

Related: Two studies look at Medicaid expansion pros,cons

The plan mostly affects two groups of people: the roughly 72million whose care is covered through Medicaid, and another 20million or so who buy insurance in the individual market.

The Senate version phases out Obamacare’s expansion of Medicaidover three years through 2023, rather than in 2020 under the Housebill. But in 2025, the Senate bill moves to more severe fundingcaps for the federal contribution to Medicaid, using the consumerprice index, rather than a measure of medical inflation that tendsto rise more quickly.

Individual market

In the individual market, the Senate bill has a subsidy systemsimilar to Obamacare, though less generous. The subsidies would bebased on the cost of a low-level bronze plan, rather than a silverplan. Silver plans have an average deductible of about $3,500,while the average for bronze plans is about $6,000, according toHealthPocket Inc., which compares health plans.

Related: 6 favorable changes to HSAs under GOP healthbill

That means individuals either must pay more to get the samehealth insurance they had before, or end up with less generoushealth plans with higher deductibles. The bill would providesubsidies for people making up to 350 percent of the poverty level,rather than the 400 percent cutoff in Obamacare.

Several Republicans are still skeptical of the measure, whichmay undergo significant changes before a Senate floor vote.

‘A number of concerns’

Republican Senator Susan Collins of Maine "has a number ofconcerns," spokeswoman Annie Clark said in a statement. Theyinclude the upcoming Congressional Budget Office analysis of manypeople would have insurance coverage, the effect on insurancepremiums and changes in Medicaid, Clark said.

GOP Senator Rob Portman of Ohio said in a statement he has "realconcerns" about the measure’s Medicaid policies.

The draft bill would provide $62 billion allocated over eightyears to a state innovation fund, which can be used for coveragefor high-risk patients, reinsurance and other items. The draft billwould phase out Obamacare’s expansion of Medicaid over three years,starting in 2021.

Among the Obamacare tax increases that would be repealed are a3.8 percent investment income tax and a 0.9 percent Medicaresurtax. The measure would delay the so-called Cadillac tax onhigh-cost plans from 2020 to 2026.

Lower subsidies

The subsidies are somewhat more generous for younger people andthose with lower incomes. A young person making 250 percent ofthe poverty level, though, would pay 4.3 percent of income for ahealth plan, down from 8.2 percent in Obamacare. Older people withhigher incomes could be required to pay as much as 16.2 percent oftheir income for health insurance, compared with a 9.7 percent capin Obamacare.

Related: Sanders signals backing of Senate slowdown overhealth care bill

To be eligible for tax credits, plans couldn’t cover abortioncosts unless the procedure is to save the life of the mother or incases of rape or incest.

Like the House bill, the Senate version effectively ends theemployer and individual mandates to buy health insurance.Republicans released a summary of the draft measure.

Republican Senator James Inhofe of Oklahoma said Thursday thatthe bill has his support.

“It does, but it’s just a starting point,” he said.

‘Heartless’ bill

Senate Minority Leader Chuck Schumer of New York said the billis "heartless" and "may be meaner" than the House version.

"This bill will result in higher costs, less care, and millionsof Americans will lose their health insurance, particularly throughMedicaid," Schumer said on the Senate floor. "It seemsdesigned to slash support for health care programs in order to givetax breaks to the very wealthy."

The plan would make fewer people who are legally present in theU.S. eligible for insurance subsidies by eliminating them for manytemporary residents and visa holders.

It also would defund Planned Parenthood for a year. AlaskaRepublican Lisa Murkowski, a supporter of the reproductive careorganization, said, "We’re going to start drafting up amendmentsand if I need to draft one on Planned Parenthood, that will be onethat we will include in the mix."

The draft bill does not, as of yet, include a provision topenalize people who don’t maintain coverage continuously, seniorGOP Senate staff said. Drafters are meeting with the CBO and Senateparliamentarian to determine whether they can include such aprovision, staff said. The House bill allows insurers to chargepeople more for coverage if they are uninsured for 63 days in ayear before signing up.

The legislation is expected to result in millions of peoplelosing insurance when evaluated by the CBO -- an estimate thenonpartisan office said it aims to release early next week. The CBOsaid the House-passed bill would result in 23 million fewer peoplewith insurance by 2026.

Republicans plan to use a mechanism allowing the bill to passthe Senate with only 50 votes, plus the support of Vice PresidentMike Pence. A Senate-passed bill would go to the House, which couldeither approve the Senate version and sending it to Trump’s desk ornegotiate a compromise version, which would then have to pass bothchambers.

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