Republicans in the U.S. House of Representatives unveiled legislation on Monday to repeal the central tenets of the Obamacare healthcare law, including its expansion of the Medicaid program for the poor and a cap on federal funding for Medicaid going forward.

Congressional Republicans and President Donald Trump have repeatedly promised to repeal and replace former Democratic President Barack Obama's signature domestic policy achievement known as the 2010 Affordable Care Act.

House Republicans didn't release a score for how much the repeal would cost – or how many Americans would lose health care coverage under the changes.

Publishing: Republicans under the leadership of Speaker Paul Ryan have unveiled their plan to repeal and replace Obamacare

The 66-page document is the prelude to an all-out battle over Obamacare with the Democrats.

House Republicans are calling their bill The American Health Care Act.

Trump made repeal and replace of his predecessor's signature plan a central point of his campaign, branding it a disaster.

White House Press Secretary Sean Spicer said: 'Obamacare has proven to be a disaster with fewer options, inferior care, and skyrocketing costs that are crushing small business and families across America.

'Today marks an important step toward restoring healthcare choices and affordability back to the American people. President Trump looks forward to working with both Chambers of Congress to repeal and replace Obamacare.'

House Ways and Means Committee Chairman Kevin Brady, R-Texas, told Fox News’ 'Special Report with Bret Baier': 'We begin by repealing the awful taxes, the mandate penalties and the subsidies in ObamaCare.'

When asked about concerns that GOP leaders are just pushing 'ObamaCare Lite', he added: 'It is ObamaCare gone.'

HIGHLIGHTS OF HOUSE GOP HEALTH CARE LEGISLATION Here are highlights of the legislation unveiled Monday by House Republicans as they move to dismantle former President Barack Obama's health care law and replace it with a system designed along conservative lines. Primarily affected would be some 20 million people who purchase their own private health plans directly from an insurer and the more than 70 million covered by Medicaid, the federal-state program for low-income people. Here's a look at some of the major components: PRIVATE HEALTH INSURANCE Provides tax credits for people purchasing their own health insurance. The subsidies would be keyed primarily to age, rising as people get older. Financial assistance would be phased out for individuals making more than $75,000 and married couples earning more than $150,000. Subsidies could be used to buy any plan approved by a state.

Eliminates cost-sharing subsidies in Obama's Affordable Care Act that helped people with modest incomes meet the costs of insurance deductibles and copayments.

States, however, would have the option of providing similar assistance with federal financing.

Greatly expands contributions to health savings accounts, which allow people with high-deductible insurance to cover expenses that their plans don't pay for.

Protects people with pre-existing health problems from being denied coverage.

However, consumers must maintain continuous coverage - otherwise, they would face a flat 30 percent surcharge on top of their premiums.

States could use federal money to create high-risk pools as insurers of last resort.

Preserves ACA provision that let young adults stay on parental coverage until they turn 26.

Allows insurers to charge their oldest customers up to 5 times what they charge young adults. The ACA limits that to 3 times.

Prohibits use of tax credits to purchase any plan that covers elective abortions. Currently if a health plan covers abortions it must collect a separate premium to pay for such procedures. MEDICAID Maintains the ACA's higher federal financing for expanded Medicaid through the end of 2019.

After that, states can only continue to receive enhanced federal payments for beneficiaries already covered by the expansion, which has mainly helped low-income adults with no children living at home.

But for newly enrolled beneficiaries, the federal government would provide a lower level of financing.

Overhauls the broader Medicaid program to end its open-ended federal financing.

Instead, each state would receive a limited amount based on its enrollment and costs.

That federal payment would be increased according to a government measure of medical inflation.

Imposes a one-year funding freeze on Planned Parenthood, a major provider of women's health services, including abortion. PENALTIES & TAXES Repeals the ACA's tax penalties on people who remain uninsured and on larger employers who do not offer coverage. The repeal is retroactive to 2016.

Repeals the ACA's taxes on upper-income earners, investors, health insurance plans and medical device manufacturers.

Repeals 10 percent sales tax on indoor tanning. COVERAGE Expected to cover fewer people than the Obama-era law, but final estimates are not yet available from the Congressional Budget Office. - Associated Press Advertisement

Central to the plan are new tax credits ranging from $2,000 to $4,000 that Americans could claim to pay for health insurance.

The repeal would effectively abolish Obamacare's individual mandate and a mandate that employers of certain businesses offer health care coverage for their employees.

The new penalties for individuals who don't get health coverage would drop to zero, as would the penalty on employees who don't offer it. The reason for affecting the change that way is that pushing legislative changes repealing Obamacare would have to clear a 60-vote threshold in the Senate. Republicans instead are opting to jam through tax and spending changes through a bill that can pass on a simple majority under budget rules.

The bill unveiled by the House Ways and Means committee also would slash away at provisions of the original Obamacare bill that paid for the program, which relied on a combination of fees, individual tax payments, and savings from Medicare to fund a system that set up new state and federal health exchanges where people could buy insurance.

The Republicans' release of bill text Monday marks the start of the next front in a major battle over the future of Obamacare

Kentucky Senator Rand Paul blasted House Republicans for failing to release the text of their bill last week

For example, the bill eliminates a tax on medical devices, a revenue source opposed by the industry.

It also phases out Obamacare's expansion of Medicaid, the health system for the poor – a portion of the bill responsible for getting millions of people onto insurance rolls.

The bill is expected to get a vote at Ways and Means and the House Energy and Commerce Committee this week and speed to the House floor, where conservative Republicans have a strong majority and have vowed for years to repeal Obamacare.

But it faces an uncertain future in the Senate, where several senators have demanded to maintain the Medicaid expansion and insisted on putting a functioning alternative to Obamacare in place.

The expansion would get frozen in 2020 and then phase out over time, Politico reported.

Meanwhile, Sens. Ted Cruz of Texas and Rand Paul of Kentucky have blasted House alternative legislation that they say commits the government to new entitlements.

Senators digging in over medicaid are Rob Portman of Ohio, Shelly Moore Capito of West Virginia, Lisa Murkowski of Alaska, and Cory Gardner of Colorado.

They wrote Senate Majority Leader Mitch McConnell of Kentucky on Monday. 'We are concerned that any poorly implemented or poorly timed change in the current funding structure in Medicaid could result in a reduction in access to life-saving health care services,' they wrote.

House Minority Leader Nancy Pelosi (D-Calif) released a statement calling the new plan 'Make America Sick Again,' saying 'hands billionaires a massive new tax break while shifting huge costs and burdens onto working families across America. Republicans will force tens of millions of families to pay more for worse coverage - and push millions of Americans off of health coverage entirely.'

Experts predicted a full repeal of Obamacare without an adequate replacement would result in 20 million people losing their health coverage, CNBC reported.

Another provision would repeal a provision that limited the tax deduction for executive pay of more than $500,000. The limit would go away in 2018.

The tax credits vary by age. People in their 30s might get tax credits of $2,500, while people in their 30s would get about $3,000 and people in their 50s would get about $3,500, with the amount capping out at $4,000.

Said House Speaker Paul Ryan in a statement: 'Obamacare is rapidly collapsing. Skyrocketing premiums, soaring deductibles, and dwindling choices are not what the people were promised seven years ago. It's time to turn a page and rescue our health care system from this disastrous law.'

Touting the GOP plan, he said: 'The American Health Care Act is a plan to drive down costs, encourage competition, and give every American access to quality, affordable health insurance. It protects young adults, patients with pre-existing conditions, and provides a stable transition so that no one has the rug pulled out from under them.'

'After years of Obamacare's broken promises, House Republicans today took an important step,' said House Energy and Commerce Committee Chairman Greg Walden of Oregon.

'Simply put, we have a Better Way to deliver solutions that put patients -- not bureaucrats -- first, and we are moving forward united in our efforts to rescue the American people from the mess Obamacare has created.'

The bill withholds funding from groups like Planned Parenthood that provide abortions using funds other than federal funds.

Two Obamacare reforms would be preserved: provisions that prohibiting health insurance companies from denying coverage to people with pre-existing conditions, and a provision that lets children stay on their parent's plans until age 26.

The bill would, however, allow insurance companies to charge higher premiums to those with pre-existing conditions who let their coverage lapse, according to CNN.

'Republicans even enable insurers to once again charge more or deny coverage to millions of Americans with pre-existing conditions, abandoning those families who lapse in coverage for any reason at all,' said Pelosi.

'Republicans have decided that affordable health care should be the privilege of the wealthy, not the right of every family in America.'

Republican leaders tried to address growing conservative opposition to the plan, imposing income limitations on the tax credits. Some House and Senate conservatives have been deriding the bill as 'Obamacare light.'