President Trump and top lawmakers Tuesday failed to craft the outlines of a spending agreement as Democrats backed out of a planned meeting at the White House amid growing acrimony over a slate of year-end legislative priorities, with a potential government shutdown looming over the negotiations.

The impasse all but ensures another holiday-season standoff over legislation designed to keep the government open and that also is expected to settle complex issues regarding immigration and health care.

Failure to act in the coming days could bring a partial shutdown of government operations, jeopardize health-care services for 9 million children and 370,000 pregnant women nationwide, and further complicate the fate of hundreds of thousands of children of illegal immigrants, known as dreamers, who could start facing deportation in early March.

“We have a lot differences,” Trump said in the White House’s Roosevelt Room, flanked by two empty chairs meant for House Minority Leader Nancy Pelosi (D-Calif.) and Senate Minority Leader Charles E. Schumer (D-N.Y.), calling Democrats weak on crime, immigration and the military. Asked about the possibility of a government shutdown this month, the president said: “If that happens, I would absolutely blame the Democrats.”

The breakdown in talks between Trump and Democrats will put more pressure on Senate Majority Leader Mitch McConnell (R-Ky.) and House Speaker Paul D. Ryan (R-Wis.), who both attended the White House meeting, to find a way forward on spending negotiations while they also race to wield their majorities to try to pass a sweeping tax bill this month.

After a rocky first year with no major legislative achievements, Republicans have a great deal at risk as the year winds down and the 2018 midterm election campaign ramps up.

While Republicans have control of Washington, GOP leaders have conceded that they will likely need Democratic votes to help pass spending bills due to potential opposition from conservatives in the House and because Senate Democrats can filibuster spending legislation.

“We need 60 votes in the Senate to close off debate and so, with 52 Republicans, we can’t do it by ourselves,” said Sen. John Cornyn (R-Tex.), McConnell’s top deputy.

Schumer and Pelosi are using this leverage to insist on adding various policy issues to win their support for the year-end funding bill.

Tensions began rising early Tuesday after Trump tweeted ahead of the scheduled meeting that Schumer and Pelosi “want illegal immigrants flooding into our Country unchecked, are weak on Crime and want to substantially RAISE Taxes. I don’t see a deal!”

Democratic aides on Capitol Hill spotted the president’s tweet and, within hours, Schumer and Pelosi agreed to skip the meeting, saying that they would rather negotiate only with McConnell and Ryan as they did in the spring to pass a similar spending plan.

Trump “now knows that his verbal abuse will no longer be tolerated,” Pelosi tweeted. “His empty chair photo opp showed he’s more interested in stunts than in addressing the needs of the American people. Poor Ryan and McConnell relegated to props. Sad!”

House Minority Leader Nancy Pelosi D-Calif.), seen on Capitol Hill in early November, skipped a meeting Tuesday after what she tweeted as “verbal abuse” by President Trump — via Twitter. (Andrew Harnik/AP)

The two GOP leaders faulted Democrats for “antics” that were putting government and military operations at risk.

“I think the Democratic leaders in the House and Senate need to understand the way the government works, and the administration has to be a part of the ultimate negotiation over what the spending level is going to be for the next year,” McConnell said at the White House.

Even before Tuesday’s standoff, Republican and Democratic aides predicted that leaders were unlikely to agree on setting new spending levels this week, meaning that Congress is likely to pass a short-term spending bill by Dec. 8, when current funding expires, that would push off negotiations until just before Christmas.

Currently, Congress may spend no more than $549 billion for defense programs and $516 billion for nondefense programs next year, a cut from current levels. But the Trump administration and defense hawks in both parties want to boost Pentagon spending to more than $600 billion, while Democrats are demanding a dollar-for-dollar increase in domestic spending.

Trump has explicitly threatened a government shutdown twice this year and Tuesday’s events signaled that prospect is increasingly more realistic.

Among Democrats, there is growing resolve to withhold support for a spending plan that fails to address the fate of dreamers. On Tuesday, Rep. Carlos Curbelo (R-Fla.), who represents a swing district in South Florida, became the first Republican lawmaker to say that he also will withhold his support for a spending bill that funds the government into next year if a solution for dreamers has not been enacted.

“Lives and livelihoods are on the line, and time is running out. We can and should get this done,” Curbelo said at an immigration policy summit at the University of Miami.

Curbelo is expected to face one of the toughest reelection fights next year and has been a key bipartisan broker on immigration policy.

Trump announced in September that he is ending the Deferred Action for Childhood Arrivals program that granted temporary legal status to roughly 600,000 young undocumented immigrants who were brought to the United States as children. He has given Congress until March to enact a permanent fix or risk mass deportations.

If Congress fails to act by March 5, DACA protections will begin to lapse, with nearly 1,000 recipients losing their status each day for two years, according to estimates. That would plunge dreamers into limbo, potentially putting them at risk of deportation while also creating havoc among businesses that employ them.

Bipartisan proposals providing permanent legal status to eligible dreamers would permit them to stay in the country, but not allow illegal immigrants to flood into the United States as Trump suggested Tuesday.

Cornyn said that resolving issues for dreamers should be handled separately from spending matters.

“I think it deserves its own consideration,” he said.

Another major sticking point for Democrats is funding for the Children’s Health Insurance Program, which began drying up on Sept. 30. Many states have enough money to keep their individual programs afloat for at least a few months, but five could run out in late December if Congress fails to act. Nearly 9 million children and 370,000 pregnant women nationwide receive care through the program.

Schumer stopped short of laying out ironclad demands that must be met in the year-end deal, but hinted that a DACA replacement, bringing defense spending increases to parity with domestic spending, funding the children’s health insurance program and providing more money for storm-ravaged states are his top priorities.

“We believe there are some things they want. There are some things we want. If you’re serious, we can negotiate a very good timely deal. And we can do it now,” he told reporters.

Schumer said he was “very hopeful” a government shutdown can be averted. He said that Republicans know “with them in charge, a shutdown falls on their back. They’re running the show.”

Sen. David Perdue (R-Ga.), a close ally of Trump, called it "irresponsible" of the Democrats to pull out of the White House meeting Tuesday. He also decried the larger pattern of fiscal brinkmanship in which both parties have engaged.

"This is ridiculous that here we are in December trying to fund the government for this year," he said. He added: "Why in the hell didn't we have this budget done and the funding done before the end of the fiscal year, back in September?"

Josh Dawsey and John Wagner contributed to this report.