A growing number of congressional Republicans are expressing opposition to President-elect Joe Biden’s $1.9 trillion economic relief proposal, complicating the incoming administration’s push to quickly inject additional aid into the ailing U.S. economy.

Congressional Republican lawmakers and aides on Friday predicted widespread GOP opposition to the plan Biden unveiled the day before, particularly over its provisions to raise the federal minimum wage to $15 an hour and provide $350 billion in state and local aid. Senior Republicans such as Senate Majority Leader Mitch McConnell (R-Ky.) had not yet commented on the measure by Friday afternoon.

Democrats will have a narrow Senate majority and could attempt to pass a relief package without any Republican votes. But doing so would require a parliamentary Senate procedure that could take time and require Biden to jettison key parts of his proposal, such as the increase in the minimum wage. Approving a relief package solely with Democratic votes would also fly against Biden’s repeated campaign pledges to unify lawmakers and cut bipartisan deals across party lines.

Biden officials this week made early overtures to the centrist congressional Republicans in the bipartisan group that broke the logjam over stimulus spending in December, according to three people granted anonymity to share details of private conversations. That group included Sens. Mitt Romney (R-Utah), Bill Cassidy (R-La.), and Susan Collins (R-Maine), among others. Major concessions to this group could spur a backlash from liberal Senators, however.

Multiple congressional Republicans from Sen. Patrick J. Toomey (R-Pa.) to Rep. Kevin Brady (R-Tex.), the top Republican on the House Ways and Means Committee, publicly panned Biden’s proposal Friday as a non-starter, although the typically GOP-friendly U.S. Chamber of Commerce issued a positive statement about the plan. Biden would need at least 10 Republican Senators to pass the measure through “regular order,” the typical path for approving legislation in the Senate.

Biden’s current proposal appeared very unlikely to command that much support in a GOP caucus already uncomfortable with the more than $4 trillion already spent by the U.S. in response to the pandemic, said Douglas Holtz-Eakin, president of the American Action Forum, a right-leaning policy group, citing conversations with numerous congressional Republican offices.

Democrats are likely to accuse Republicans of hypocrisy if they resist higher spending in response to the pandemic. The national debt increased by almost $7.8 trillion during President Trump’s tenure, rising to levels unseen since World War II, partly because of the GOP’s $1.5 trillion unpaid-for tax cut bill.

“We have to get serious about how we’re spending taxpayer dollars,” Sen. Rick Scott (R-Fla.) said in a statement. “We cannot simply throw massive spending at this with no accountability to the current and future American taxpayer.”

With the pandemic surging and the economy shedding jobs, Democrats have signaled that they are prepared to pass legislation without Republican votes. Sen. Bernie Sanders (I-Vt.), the incoming chairman of the Senate Budget Committee, has said he wants to move aggressively to pass a bill via the budget process known as “reconciliation,” which only requires a majority vote in the Senate. Some budget experts say that an increase in the minimum wage would be rejected by Senate parliamentarians if attempted through reconciliation.

Moving legislation without Republican votes would present its own challenges given divisions among Democrats and the party’s narrow majorities in both chambers. The Senate will be divided 50-50 between Republicans and Democrats in the new Congress, with Democrats in the majority only because Vice President-elect Kamala Harris will be in the position to cast tie-breaking votes once Biden is inaugurated Jan. 20.

That means any individual Democratic senator could hold up the legislation with any number of demands.

The Democrats’ 222-211 House majority is also the smallest of any party in years, meaning Biden will have to work with congressional leaders to navigate competing factions in the caucus.

House Speaker Nancy Pelosi (D-Calif.) and incoming Senate Majority Leader Charles E. Schumer (D-N.Y.) played a behind-the-scenes role in shaping the package Biden laid out Thursday, urging transition officials to reach for a higher pricetag than initially envisioned, according to two people who requested anonymity to disclose the private conversations. That bigger number helped the package win applause from Sanders and a number of other liberals, but also made it is less likely to attract GOP support.

Pelosi cheered Biden’s proposal Friday and urged swift passage.

“He is delivering on what he said when he was elected — help is on the way. This plan makes big bold urgent action building on some of our Democratic initiatives in the last Congress,” Pelosi said at a news conference.

The proposal includes multiple provisions to speed vaccine production and increase testing, help schools reopen, and send direct relief to individuals, communities and businesses.