After the report's release, the Trump administration quickly criticized its conclusions, saying it does not take into account other administrative actions it plans to take after the bill is passed.

The GOP proposal would reduce the federal deficit by $337 billion over the next decade, the CBO said. Premiums in the individual market would be on average 15 to 20 percent higher in 2018 and 2019 than under current law. By 2026, though, they would be 10 percent lower than if Obamacare remained intact.

The CBO estimated that 14 million more people would become uninsured next year . By 2026, if the top Republican proposal to replace Obamacare becomes law, 24 million more people would be uninsured than would be under current law. The report said 52 million people would be uninsured in 2026 if the legislation becomes law, compared with 28 million, if not.

Key Congressional Democrats pounced Monday on an analysis that said millions more would be uninsured under the Republican Obamacare replacement plan, while some top GOP lawmakers saw an affirmation of their approach.

Democrats slammed the estimated rise in uninsured people and raised concerns that seniors would see the brunt of the cost increases. House Speaker Paul Ryan, meanwhile, highlighted its estimated effect on the deficit and maintained that it would increase consumer choice and bring down costs.

The reactions most crucial to the bill's future may come from other pockets of the Republican Party, like moderate GOP senators and conservative representatives whose concerns about the bill threatened its passage. Moderate Republicans may raise concerns about the CBO's estimates related to Medicaid, which it said would fuel in large part the rise in uninsured people.

Senate Minority Leader Chuck Schumer, D-N.Y., argued the CBO reports shows the plan will "cause serious harm to millions of American families."

"The CBO score shows just how empty the president's promises that everyone will be covered and costs will go down, have been," he said, in a statement.

House Democratic leader Nancy Pelosi also expressed concerns that the plan's tax cuts distribute wealth to higher-income Americans at the expense of lower-income people.

Ryan, conversely, said the report shows that "when people have more choices, costs go down."

Trump on Monday echoed his earlier sentiment that letting the ACA fail on its own could prove more politically wise for Republicans than repealing it because of the possible backlash from people losing coverage.

"The Republicans, frankly, are putting themselves in a very bad position — I tell this to (Health and Human Services Secretary Tom Price) all the time — by repealing Obamacare," Trump said during a White House session with people he called "victims" of Obamacare. He argued that the system would eventually implode, and said letting it do so is "certainly an option" though not one he likes.

The Trump administration started to cast doubts on the accuracy of the CBO report days before its release. They contended that the nonpartisan committee may not capture the effects of the American Health Care Act because it has made errors in scoring health care in the past.

"If you're looking to the CBO for accuracy, you're looking in the wrong place," White House press secretary Sean Spicer said last week.

National Economic Council Director Gary Cohn called the score "meaningless" on "Fox News Sunday."