WASHINGTON — Conservatives on the House Budget Committee on Friday blocked their party’s megabill from reaching the floor, citing concerns that the legislation to fulfill President Donald Trump’s domestic agenda would add too much to the deficit.

It was a remarkable revolt that threatened to upend the party’s goal of pushing the legislation through the House before its Memorial Day recess and sent Republican leaders scrambling to try to put down the uprising.

The setback underscored the treacherous balancing act that Speaker Mike Johnson is trying to pull off. Without the support of Republican hard-liners on the Budget Committee, the bill cannot advance. But any changes to win their backing could alienate the more moderate Republicans whose votes will also be needed to pass the measure on the House floor.

Five Republican representatives — Chip Roy of Texas, Ralph Norman of South Carolina, Josh Brecheen of Oklahoma, Andrew Clyde of Georgia and Lloyd Smucker of Pennsylvania — joined Democrats in voting to block the legislation. The 21-16 vote failed to advance the bill.

“This bill falls profoundly short; it does not do what we say it does with respect to deficits,” Roy said before the vote, explaining his opposition. “Deficits will go up in the first half of the 10-year budget window and we all know it’s true, and we shouldn’t do that. We shouldn’t say that we’re doing something we’re not doing.”

A few hours after the vote failed, committee leaders announced that the panel would reconvene Sunday at 10 p.m. to reconsider the legislation. It was not clear what, if any, changes Republican leaders agreed to before calling lawmakers back.

But immediately after the vote, they had not seemed optimistic: The committee’s chair, Rep. Jodey C. Arrington of Texas, told its members they could return home to their districts.

“Well, the noes have it,” Arrington said. “I want to thank everybody for their time and patience, and Godspeed and safe travels.”

Smucker, who changed his “yes” vote to a “no” vote at the last minute, said he did so for procedural reasons. Because he voted against the bill, he will be able to ask to call the legislation back up for consideration once Republicans broker a deal.

The legislation the party is trying to push through would make Trump’s 2017 tax cuts permanent and eliminate taxes on tips and overtime pay through 2028, fulfilling a campaign pledge.

Cuts to Medicaid, food stamps and subsidies for clean energy would partly offset the roughly $3.8 trillion cost of those tax measures over 10 years, as well as increased spending on the military and immigration enforcement.