Kentucky Sen. Rand Paul responds to a question during a meeting of the Economic Club of Las Vegas at Caesars Palace in Las Vegas on Dec. 16, 2015. (Steve Marcus/Las Vegas Sun via AP)

President-elect Donald Trump may be joining the growing ranks of Republicans in Washington who are getting cold feet about plans to rush through a vote to repeal Obamacare without a plan to replace it.

Trump called Sen. Rand Paul (R-Ky.) this weekend to discuss Paul’s push to convince the rest of the GOP not to vote later this week on a budget resolution that includes a framework for a vote to repeal the Affordable Care Act without a replacement plan. Paul said he spoke with Trump for approximately 15 minutes Friday and the two agreed on the need for replacement.

The only hitch: Republicans don’t have one yet.

“He showed willingness and openness and was interested in getting a replacement that could be passed as part of repeal,” Paul said. “Now, we’re trying to get a bill out there this week.”

Paul said Trump didn’t give additional details on what he would like to see in a replacement plan. Republican leaders have insisted in recent weeks that they are working on a plan that will help those who receive coverage through the Affordable Care Act to buy insurance on the private marketplace, but like Trump, few have offered any specifics.

Trump said Monday that he had no concerns about the lack of a plan or growing worries about repeal.

“Not even a little bit. That’s going to all work out,” Trump said Monday outside of Trump Tower in New York.

House Speaker Paul D. Ryan (R-Wis.) insisted to reporters last week that Republicans do have a plan — just not one that is ready to be released this week.

“We have plenty of ideas to replace it,” Ryan said. “You’ll see, as the weeks and months unfold, what we’re talking about replacing it — how we can get better choices with lower prices by not having a costly government takeover of health care, which is causing all this problem in the first place.”

A growing number of Republicans have raised concerns in recent days about aggressively gutting major portions of the health-care law — including eliminating penalties for people who do not have insurance and the federal subsidies that help people buy insurance — in the coming months. Leaders have said those changes would not go into effect for several years to give committees time to pass a replacement.

Some Republicans, including Paul, have floated bits and pieces of a potential replacement, but there is widespread disagreement over who should be on Medicare and Medicaid and whether it is possible to promise that everyone who is insured under Obamacare will be able to find coverage under a GOP plan.

“My view is that replacement should try to get insurance for as many people as possible,” Paul said. “The administration likes to say that 20 million people are covered now. Well, 85 to 90 percent of that number got Medicaid. Many were already qualified for Medicaid. So a lot of debate goes into these numbers.”

Others, such as Sen. Bill Cassidy (R-La.), have pitched plans that allow states more leeway. His plan would allow individual states to retain exchanges and would include a tax credit to help people buy insurance on the private market. Cassidy said Monday that he wants to move quickly to repeal “onerous” parts of the health-care law, such as the requirement for individual health coverage, as long as there is a plan and timeline for completing a replacement.

“As long as we have a sense of where we’re going, I’m okay with that,” Cassidy said.

The Senate is expected to vote this week on a budget measure that includes instructions for committees to write repeal legislation by the end of the month. But some Republicans are raising concerns that a replacement may never happen if it is delayed.

“I think the vast majority of people believe we’re better off doing both at one time. The question is, can you really make that happen?” Sen. Bob Corker (R-Tenn.) said Friday.

But it is far easier for Congress to pass a repeal bill than it is for it to pass any kind of replacement. Republican leaders are relying on special budget procedures to repeal Obamacare without the threat of a blockade by Senate Democrats.

Budget legislation can pass the Senate with a majority of 51 votes rather than the normal 60 needed for almost everything else. There are 52 Republicans in the Senate, ensuring that a unified GOP can act without the help of Democrats.

But passing a replacement is another story. Any new health-care legislation would be subject to normal Senate rules — meaning Republicans would need votes from at least eight Democrats to get the new bill passed.

“We’re possibly creating a boxed canyon for ourselves by potentially repealing without replacing,” Corker said. “On the other hand, I realize the difficulties of getting — the other way you need 60 votes, right? And I don’t see a lot of appetite by Democrats to sit down and try to work some things through.”

Democrats have said that they are not interested in helping the GOP dismantle President Obama’s health-care law.

“Show us what they are going to replace it with, not just one senator,” said Senate Minority Leader Charles E. Schumer (D-N.Y.) on Monday. “Or they abandon repeal.”

Sean Sullivan contributed to this report.