WASHINGTON A harsh Congressional Budget Office assessment of the Republican House bill to repeal the Affordable Care Act had GOP senators on Tuesday calling for changes, including more financial assistance for low-income Americans.

Senate leaders did their best to dismiss the nonpartisan CBO review of the legislation, which found it would increase the number of people without insurance by 14 million in the first year, and by 24 million within a decade nearly double the estimate for Obamacare. Still, some GOP senators said they were concerned with the House legislations potential effects on low-income people, seniors and Medicaid patients.

Of particular concern to these senators was the way the GOP bill would redirect health insurance tax credits, leaving the poorest consumers with less money than they get under the Affordable Care Act.

I do think there are things that we can do to tailor the tax credit in a way that makes it more attractive to people, and more helpful to people on the lower end, and with a phase-out that is a little less steep than what the House proposes, Sen. John Thune (R-S.D.) told reporters Tuesday.

Thune said itd be nice if House Republicans made the tax credits available in the legislation more generous for older Americans before it comes to the Senate, but said he was already working on a potential amendment. Two top Republicans Sens. Lamar Alexander (Tenn.) and Roy Blunt (Mo.) agreed changes to help lower-income people were needed .

Other senators raised complaints at the weekly caucus meeting, which also included Vice President Mike Pence and Health and Human Services Secretary Tom Price, and key House Republicans Greg Walden (Ore.), chair of the Energy and Commerce Committee, and Kevin Brady (Texas), chair of the Ways and Means Committee.

Senators found an array of faults with the legislation, raising a challenge for GOP leaders trying to craft a cohesive message.

There are multiple different points that are brought up and I guess the difficulty is keeping everybody in the basket as they make an attempt to address issues, Sen. Bob Corker (R-Tenn.), said after the caucus meeting. The [states that didnt expand Medicaid] have different issues than the expansion states.The states with older populations have different issues than those with younger populations.

While senators criticized the CBO Blunt said its analysts are notoriously bad at anticipating whats going to happen in a marketplace they were happy to hype CBO findings they liked. That included a projection that the bill would reduce the deficit by $337 billion over 10 years, mostly because of those big cuts to Medicaid. Republicans also highlighted the prediction that premiums would fall 10 percent by 2026, compared with what they would be under Obamacare.

But the CBO estimates came with two important caveats that Senate leaders neglected to mention. One was that premiums would be lower, in part, because the insurance would cover less leaving people with higher out-of-pocket costs . The other is that older people may face sky-high premiums under the GOP measure and may drop coverage altogether. Thats because insurers would have more flexibility to vary prices by age.

AARP has been slamming the legislation since it was introduced, and Sen. Bill Cassidy (R-La.) made clear the CBO findings on the subject weighed on his mind. Folks who are over 60 earning $20,000 a year would have a hard time affording insurance, and thats not good, Cassidy said.

Cassidy, who has co-sponsored an alternative proposal, stopped well short of declaring that higher premiums for seniors were a deal-breaker. But he did say the Senate needed time to consider whether changes would improve the legislation.

There needs to certainly be deliberation and something that ameliorates peoples concerns, Cassidy said.

Sen. John Boozman (R-Ark.) said he worried about the estimated 300,000 people who signed up for Medicaid after his state expanded the program under Obamacare. That helped lower the number of uninsured people in the state by more than 50 percent, according to statistics at healthinsurance.org .

Im concerned about Medicaid expansion and making sure people are taken care of, and again, thats why Im going to figure out whats going on, Boozman said.

Sen. Ted Cruz (R-Texas), wasnt worried about Medicaid perhaps because Texas hasnt expanded the program. Cruz said he feared leaving some Obamacare regulations in place would keep premiums high.

Under the CBO report, they dont ever go down, Cruz said. They simply increase a little bit slower than they would increase under Obamacare. That is not the mandate that we were elected to fulfill.

The House bill as drafted wont pass in the Senate, Cruz added.

Sen. Tom Cotton (R-Ark.) and Sen. Steve Daines (R-Mont.), also raised objections.

House GOP leaders plan a floor vote next week, less than a month after the measure was introduced. Thats breakneck speed for any legislation, not just a bill of this magnitude.

Senate Majority Leader Mitch McConnell (R-Ky.) has said he intends to bring whatever the House passes directly to the Senate floor, bypassing committees. He said on Tuesday that the bill would be open to amendment when it reaches the Senate.

Boozman noted that Republicans were taking on a big challenge, with a lot of potential to get something wrong.

This is difficult, Boozman said. Its 18 percent of economy. My concern is not with the timeline. My concern is with doing it right. We dont need to do something, we need to do the right thing.