The U.S. House of Representatives' Republican leader said on Tuesday that legislation to replace former President Barack Obama's signature healthcare law would be completed this year, trying to dispel the idea that the party is retreating from its campaign promise to dismantle Obamacare quickly.

"The question is how long does it take to implement the full replacement of Obamacare," House Speaker Paul Ryan told a news briefing. "We hope to get this done as fast as possible."

Ryan was responding to questions about Republican President Donald Trump's weekend interview with Fox News in which he said it might take until next year to replace the Affordable Care Act, popularly known as Obamacare, which Republicans consider federal government overreach.

Trump and congressional Republicans campaigned on a promise to scrap the 2010 healthcare law. But they are struggling to agree on a replacement for the law, which has enabled up to 20 million previously uninsured Americans to obtain health coverage.

"Maybe it'll take till sometime into next year," Trump said.

On Tuesday at the White House, spokesman Sean Spicer said the administration was "optimistic about getting this thing completed by this year."

Spicer also said Trump still favors lowering drug prices as part of healthcare reform, with the government negotiating directly with companies on prices to be paid by the Medicare insurance program.

Spicer said Trump was committed to using his "skills as a businessman" to drive pharmaceutical prices down.

Ryan said it was important to get U.S. Representative Tom Price confirmed as secretary of the Department of Health and Human Services soon, so he too can "get to work with replacing" the healthcare law. The Senate is expected to confirm Price this week.

Ryan said he was not bothered by recent protests against dismantling Obamacare that have taken place at some Republican lawmakers' meetings with constituents. "Peaceful protests are something we honor in this country," he said.

While Republicans voted last month to start scrapping Obamacare, they missed a target date of Jan. 27 to begin drafting legislation. This raised some doubts about how quickly they will be able to undo the complicated law, even though they have the majority in Congress.

At a recent congressional retreat, Republican leaders told lawmakers they hoped Congress would legislate the repeal by March or April, as part of a process known as budget reconciliation. But some Republicans, like Representative Tom McClintock, have said they think doing it this way will actually make repealing Obamacare "harder and slower, while further disrupting an already faltering healthcare market."