Washington • Congress prepared to return to work Saturday as negotiators pressed for a budget deal to keep a government shutdown that began at midnight short-lived.

Agencies shut down for the first time in more than four years late Friday after senators rejected a temporary spending patch and bipartisan efforts to find an alternative fell short as a midnight deadline came and went.

Republican and Democratic leaders both said they would continue to talk, raising the possibility of a solution over the weekend. Office of Management and Budget Director Mick Mulvaney said Friday that the conflict has a “really good chance” of being resolved before government offices open Monday, suggesting that a shutdown’s impacts could be limited.

But when the House reconvened Saturday morning, the partisan finger-pointing began immediately.

“Democrats in the United States Senate are holding government funding hostage. The people protecting this country will continue to work but won’t get a paycheck,” Rep. Virginia Foxx, R-N.C., said in a floor speech.

House Minority Whip Steny Hoyer, D-Md., shot back from across the aisle: “It is the Trump confrontation and chaos that continues. That is why this government is shut down.”

House Republicans and Democrats planned to hold separate caucus meetings at 10 a.m. to plot the hours ahead. The Senate is scheduled to convene at noon, but it is unclear when senators might vote Saturday — if at all.

With lawmakers clamoring for a deal, the White House drew a hard line immediately after midnight, saying they would not negotiate over a central issue — immigration — until government funding is restored.

“We will not negotiate the status of unlawful immigrants while Democrats hold our lawful citizens hostage over their reckless demands,” White House press secretary Sarah Huckabee Sanders said in a statement. “This is the behavior of obstructionist losers, not legislators. When Democrats start paying our armed forces and first responders we will reopen negotiations on immigration reform.”

President Donald Trump took to Twitter on Saturday morning to lay the blame on Democrats, saying they “are far more concerned with Illegal Immigrants than they are with our great Military or Safety at our dangerous Southern Border. They could have easily made a deal but decided to play Shutdown politics instead.” He also noted in a follow-up tweet that Saturday is the first anniversary of his inauguration and that “the Democrats wanted to give me a nice present.”

Both parties confronted major political risks with 10 months to go until the midterm elections. Republicans resolved not to submit to the minority party’s demands to negotiate, while Democrats largely unified to use the shutdown deadline to force concessions on numerous issues - including protections for hundreds of thousands of young undocumented immigrants.

The standoff culminated in a late-night Senate vote that failed to clear a 60-vote hurdle, sending congressional leaders and Trump back to the starting line after days of political posturing on all sides.

“A government shutdown was 100 percent avoidable. Completely avoidable. Now it is imminent,” Senate Majority Leader Mitch McConnell, R-Ky., said on the Senate floor following the vote. “Perhaps across the aisle some of our Democratic colleagues are feeling proud of themselves, but what has their filibuster accomplished? ... The answer is simple: Their very own government shutdown.”

The early contours of the blame game appeared to cut against Trump and the Republicans, who control all levers of government but cannot pass major legislation without at least partial support from Senate Democrats. According to a Washington Post-ABC News poll released Friday, Americans said by a 20-point margin that they would blame a shutdown on Trump and the GOP rather than Democrats.

A government shutdown causing employee furloughs has never occurred under unified party control of Congress and the White House. Some furloughs of White House employees began immediately early Saturday.

One possible path out of the impasse appeared in wee hours: Sen. Jeff Flake, R-Ariz., leaving the Senate floor, said that he had secured an agreement from McConnell to bring a bipartisan bill addressing “dreamers” — young immigrants brought to the United States illegally as children - up for a vote.

Flake said he expected a short-term spending deal to be agreed to during Saturday’s Senate session, extending government funding through Feb. 8. By that same date, Flake said, McConnell would move to bring up a bill crafted by a bipartisan group of senators led by Richard J. Durbin, D-Ill., and Lindsey O. Graham (R-S.C.).

McConnell had previously made a similar commitment to Flake, but the majority leader insisted in recent days that any immigration-related bill would have to be one Trump supported. Flake said he had urged him, and McConnell had agreed, not to wait on the president.

“At this point, we agree we can’t wait for the White House anymore,” Flake said.

A McConnell spokeswoman did not immediately comment Saturday morning on Flake’s account of a deal.

The shutdown began after an unusually tranquil day inside the Capitol, where visible tensions remained at a low simmer as various parties undertook quiet talks to discuss ways to avoid the shutdown.

Republicans started the day eager to show a united front: House Speaker Paul Ryan, R-Wis., and McConnell met Friday morning, determined to hold firm to a strategy they had crafted nearly a week prior: Make Democrats an offer they could not refuse by attaching a long-term extension of the Children’s Health Insurance Program, or CHIP, as well as the delay of some unpopular health-care taxes. And if they did refuse, the leaders believed, the public backlash would be intense — particularly in states where vulnerable Democratic senators are seeking reelection in November.

But by midday, McConnell’s strategy threatened to be upended by Trump - who phoned Schumer and invited him to the White House for a private meeting with no other congressional leaders.

That immediately raised Republicans’ suspicions on Capitol Hill that Trump might be tempted to cut a deal with his fellow New Yorker — much as he did in the early stages of a September standoff — that would undercut the GOP negotiating strategy and produce a deal that congressional conservatives could not stomach.

White House aides assured top congressional leaders that no deal would emerge from the meeting, that it was merely meant to gauge the posture of Schumer and the Democrats. Republicans exhaled when that turned out to be so.

Trump and Schumer talked over a cheeseburger lunch, according to a person familiar with their conversations, covering a wide range of contentious issues. Later on the Senate floor, Schumer described a meeting where he forged outlines of a potential deal with Trump, only to see it fall apart once he left the room.

“I reluctantly put the border wall on the table for discussion — even that was not enough to entice the president to finish the deal,” he said, adding: “What has transpired since that meeting in the Oval Office is indicative of the entire tumultuous and chaotic process Republicans have engaged in the negotiations thus far. Even though President Trump seemed to like an outline of a deal in the room, he did not press his party in Congress to accept it.”

What ensued for the remainder of the afternoon was a silent standoff, as it became increasingly clear that Republicans would not be able to lure enough Democrats to pass their preferred funding patch.

The Trump administration worked up plans to keep national parks and monuments open despite a shutdown as a way to blunt public anger, and while the military would not cease to operate, troops would not be paid unless Congress specifically authorizes it. After the shutdown began, senators rejected a proposal from McCaskill to keep paying troops during the impasse and allow most civilian Defense Department employees to keep working.

Usually, Congress quickly votes after a shutdown ends to pay service members and federal employees not compensated during the lapse in funding.

Trump postponed a scheduled trip to his Florida resort, where he had scheduled a pricey fundraiser to mark his first anniversary in office. Ryan faced the cancellation of an official trip to Iraq, and House Majority Leader Kevin McCarthy, R-Calif., and other lawmakers revisited plans to travel to Davos, Switzerland for the World Economic Forum.