President Trump and congressional Democrats are digging deeper into their trenches over funding for a wall on the Mexican border, prolonging a government shutdown that seems almost certain to head into the next year.

Both the House and Senate on Thursday conducted brief, minutes-long pro forma sessions before quickly gaveling out.

In the Capitol building, there was little sign of work, and visitors were more likely to see reporters, security guards or fellow tourists than a working member of Congress.

“The President and his team stayed in Washington over Christmas hoping to negotiate a deal that would stop the dangerous crisis on the border, protect American communities, and re-open the government. The Democrats decided to go home,” White House press secretary Sarah Sanders said in a Thursday statement released as the Senate was adjourning.

A spokesman for Rep. Nancy Pelosi (D-Calif.), who is set to be elected House Speaker on Jan. 3 after Democrats take the House majority, responded a short time later, saying Democrats would pass a bill to reopen the government when they took power if the GOP did not act.

“Democrats have offered Republicans three options to re-open government that all include funding for strong, sensible, and effective border security – but not the President’s immoral, ineffective and expensive wall,” Pelosi spokesman Drew Hammill wrote in a tweet.

“With the House Majority, Democrats will act swiftly to end the Trump Shutdown, and will fight for a strategic, robust national security policy, including strong and smart border security, and strong support for our servicemembers and veterans,” he wrote.

Reuters released a poll indicating that more people are blaming Trump than Democrats for the shutdown.

The Reuters/Ipsos online poll found that 33 percent blamed Democrats in Congress for the shutdown, compared to 47 percent who blamed Trump. Another seven percent blamed Republicans in Congress, while 12 percent blamed “other.” Just 35 percent of those surveyed said they wanted Congress to fund the wall.

But Trump showed no signs of backing down, stating in a morning tweet that many of the people losing paychecks as a result of the shutdown were Democrats. He later blamed Democrats for backing away from a deal earlier this year that would have exchanged funding for the wall for language to protect “Dreamers” — immigrants who entered the U.S. illegally as children.

That deal actually collapsed after the White House added to its demands, calling for changes to other legal immigration programs that would have lowered the number of people able to immigrate to the United States.

If Democrats do pass legislation through the House to reopen the government after they take back the majority, it’s not clear what the Senate will do.

The Senate majority will remain in GOP hands, and Majority Leader Mitch McConnell (R-Ky.) will have to decide whether to bring legislation to a vote.

“I think it’s clear that we on the Republican side don’t want to vote for a bill that the president won’t sign,” said Sen. PatRoberts (R-Kansas), who led Thursday’s pro forma Senate session.

The shutdown standoff began after the Senate passed by voice vote a bill to keep the government open through Feb. 8. That bill did not meet Trump’s demand for $5 billion in wall funding, but at the time, McConnell seemed to think it would pass the House and be accepted by Trump.

That quickly changed after House conservatives complained to Trump and insisted they’d have his back on the wall. The House then voted for legislation that also funded the government through Feb. 8 that included $5.7 billion in money for the wall and border security.

Rep. Mark Meadows (R-N.C.), the chairman of the conservative House Freedom Caucus, encouraged Trump to stick to his guns, and blamed Democrats for not supporting wall funding.

“At this point, it looks like we could be in for a very long-term shutdown,” he said on CNN Thursday.

It’s also possible that Trump could veto legislation sent by Congress that does not meet his demands, and it’s unclear if there would be enough votes to override his veto. Many Republicans would be under enormous pressure to back Trump on his signature campaign promise.

Rep. Jim McGovern (D-Mass.), the top Democrat on the House Rules Committee, sought unsuccessfully to pass a clean funding bill during the House’s pro forma session Thursday.

He said House GOP leaders were showing little interest in ending the shutdown, suggesting they might prefer to hand the issue to Pelosi.

“I worry that this departing Republican leadership has no sense of urgency,” McGovern said. “If I were them and I were leaving, I wouldn’t want to leave a mess behind, and they seem totally content to leave this place in total chaos and a total mess and I just find that really disheartening. But if they don’t do their work, then we’re going to have to do it the first day we get back.”

One possible way out for both sides would be to approve legislation to fund a non-wall barrier, something Democrats have been more open to supporting.

“We can call it anything we want to: barrier, fence. I won’t say the W word,” Roberts said Thursday.

Trump himself this week seemed to soften his position, saying the government is “not going to be open until we have a wall, a fence — whatever they’d like to call it. I’ll call it whatever they want, but it’s all the same thing; it’s a barrier from people pouring into our country.”

In another sign of possible flexibility from Trump, a White House official said they had offered a deal of $2.1 billion in border security funding, but that Democrats did not bite. The remarks by the official could also be seen as an effort to cast Democrats as the intransigent side in the debate.

The shutdown has left 800,000 federal employees furloughed or forced to work without pay through the holidays. On Thursday, the Office of Personnel Management Tweeted sample letters as a guide on how to negotiate with creditors for federal workers facing financial difficulty.

“I am a Federal employee who has recently been furloughed due to a lack of funding of my agency. Because of this, my income has been severely cut and I am unable to pay the entire cost of my monthly payments, along with my other expenses,” one sample letter read.

Though workers were expected to receive paychecks this week covering all but one day of their pay period, a prolonged shutdown could mean delays until their next check. While federal employees typically are given pack pay after a shutdown, many federal contractors will not be paid for the period of the shutdown.

Naomi Jagoda and Jordan Fabian contributed to this story.