House Speaker Mike Johnson's suggestion that Republicans would implement "massive reform" to the Affordable Care Act -- known as Obamacare -- is causing a bit of a headache for the Trump campaign.

At a campaign event Monday in Pennsylvania, a battleground state in the presidential race, Johnson made that assertion.

"No Obamacare?" an attendee of the event asked Johnson.

"No Obamacare," Johnson replied. "The ACA is so deeply ingrained, we need massive reform to make this work, and we got a lot of ideas on how to do that."

Johnson did not elaborate on specifics but said Republican doctors in the House, known as the GOP Doctors Caucus, have been working on possible legislative ideas. The speaker said Republicans want to "take a blowtorch to the regulatory state" and "fix things" in the health care sector.

Health care is a key issue in the 2024 election and both parties have different views on the ACA, which set minimum benefit standards, allowed more people to be eligible for Medicaid and ensured consumers with preexisting conditions could have health care coverage.

"Health care reform is going to be a big part of the agenda. When I say we're going to have a very aggressive first 100 days agenda, we got a lot of things still on the table," he said.

The speaker said "if you take government bureaucrats out of the health care equation and you have a doctor patient relationship it is better for everybody, more efficient more effective. That's the free market. Trump is going to be for the free market."

The Harris campaign sharply criticized Johnson's comment. Spokesperson Sarafina Chitika said in a statement, "Speaker Mike Johnson is making it clear – if Donald Trump wins, he and his Project 2025 allies in Congress will make sure there is 'no Obamacare.' That means higher health care costs for millions of families and ripping away protections from Americans with preexisting conditions like diabetes, asthma, or cancer. Voters see Trump's 'concepts of a plan' for what they are: Ending the Affordable Care Act, jacking up prices, and leaving millions of Americans without the care they need."

Former President Donald Trump's campaign quickly tried to separate itself from the speaker's comments. A spokeswoman told the New York Times that they were “not President Trump’s policy position.”

The ACA has become increasingly popular since it was enacted in 2010. A KFF poll in February found that two-thirds of the public said it was very important to maintain the law's ban on charging people with health problems more for health insurance or rejecting their coverage.

Former President Donald Trump tried and failed to repeal the ACA while he was in office.

"Obamacare was lousy health care. Always was," Trump said at ABC's presidential debate. "It's not very good today and, what I said, that if we come up with something, we are working on things, we're going to do it and we're going to replace it."

Pressed for details on what he would replace it with, Trump said he did not have a specific plan in place, but rather "concepts of a plan."

NBC News first reported the speaker's remarks.