Republicans fired back Tuesday at a report from the Congressional Budget Office warning that premiums would soar and 18 million more would be uninsured in a year if they make good on their promise to kill parts of ObamaCare without a replacement.

The new report said under such a measure, premiums for individual policies - excluding the coverage many workers get from employers - would swell by up to 25 percent the first year after enactment and double by 2026. The number of uninsured would reach 32 million over the decade, the analysts said.

Republicans, however, say there's a big difference between that 2016 bill and this year's plan: Last year's version would not have replaced Obama's statute with a GOP alternative, while Republicans insist replacement will be an integral part of their new health care drive.

Citing that difference, Donald Stewart, spokesman for Senate Majority Leader Mitch McConnell, R-Ky., said the report "assumes a situation that simply doesn't exist and that no one in Congress advocates." AshLee Strong, spokeswoman for House Speaker Paul Ryan, R-Wis., called the estimates "meaningless" because they ignore plans for legislation and regulatory actions by the incoming Trump administration for revamping how people could obtain coverage.

Republicans have produced several outlines for how they'd redraft Obama's 2010 statute, but they've failed to unite behind one plan. President-elect Trump and GOP congressional leaders have at times offered clashing descriptions of their shared top goal, so eventual success is hardly guaranteed.

Tuesday's evaluation came from the nonpartisan Congressional Budget Office, joined by Congress' Joint Committee on Taxation.

Together, they analyzed a Republican-written bill, vetoed by Obama last January, that would have erased major portions of his overhaul. Those included tax penalties for people who fail to buy insurance and for larger companies that don't cover workers, federal subsidies to help consumers buy policies on the law's online marketplaces and an expansion of Medicaid coverage for low-income people.

Democrats seized on the report.

"Nonpartisan statistics don't lie," countered Senate Minority Leader Chuck Schumer, D-N.Y., who said the report showed Republican plans to void Obama's overhaul "will increase health care costs for millions of Americans and kick millions more off of their health insurance." House Minority Leader Nancy Pelosi, D-Calif., said it illustrated that the GOP effort "will be nothing less than a nightmare for the American people."

Trump seemed to complicate the GOP drive last weekend when he told The Washington Post that a forthcoming Republican plan would provide "insurance for everybody." In contrast, some congressional Republicans have described their goals more modestly, saying they will offer "universal access."

CBO said that under the 2016 Republican bill, the number of insured people would fall mostly from annulling the tax penalties Obama's law imposes on people who don't buy policies: Some people would simply drop out if not forced to buy insurance. In addition, some insurers would leave individual insurance markets as consumers stopped buying coverage.

Some 59 million people under age 65 - about 1 in 5 - would be uninsured by 2026, the report said, compared to 28 million under Obama's law.

The Associated Press contrributed to this report