Talks toward ending the partial government shutdown hit a new low Wednesday when fireworks broke out at the White House, with President Donald Trump abruptly leaving a meeting with congressional leaders after yet another flap over his proposed southern border wall.

The shutdown enters its 20th day Thursday with no end in sight after another round of fruitless talks and blunt warnings from Trump about his next possible move if he cannot secure a deal with congressional Democrats over his border wall demands — even as 800,000 federal workers and their families wonder about future paychecks.

During several rounds of talks, White House officials and Democratic leaders have only agreed to a few items included in a spending proposal submitted to lawmakers Sunday. But they have not agreed to the giant sticking point keeping nine Cabinet agencies and other smaller offices shuttered: the border wall. And, on Wednesday, they couldn’t even agree on the president’s tone and actions as he ended the Situation Room session after just a few minutes.

“The president stomped out of the meeting,” Speaker Nancy Pelosi said. Senate Minority Leader Charles E. Schumer called Trump’s move a “temper tantrum,” contending the president at one point “slammed the table” before calling the meeting “a waste of his time.”

Republican leaders, under blustery and snowy skies outside the White House, took umbrage with that account by their Democratic counterparts, saying Trump never slammed anything and, as Vice President Mike Pence recalled, he even “passed out candy” as they got underway.

Just left a meeting with Chuck and Nancy, a total waste of time. I asked what is going to happen in 30 days if I quickly open things up, are you going to approve Border Security which includes a Wall or Steel Barrier? Nancy said, NO. I said bye-bye, nothing else works!

— Donald J. Trump (@realDonaldTrump) January 9, 2019

Pence told reporters Trump “calmly” asked Pelosi if she would pass legislation with border barrier funding if he agreed to reopen the shuttered federal agencies. When she said no, “the president said goodbye,” Pence said.

Watch: Trump says no sign of GOP disunity, may still declare national emergency

The drama only left the two sides drifting further apart, and it came after Trump appeared to sense new leverage in the standoff after he opted against declaring a national emergency at the southern border during a Tuesday prime-time address from the Oval Office — and he wasted little time in deploying it. At several points Wednesday, the president told reporters — as he did Senate Republicans in a closed-door lunch meeting at the Capitol — that if a deal cannot be reached soon, he will make the emergency declaration, allowing him to access military funds for the steel barrier.

[Trump urges Senate Republicans to ‘just hang together’ on border battle]

“Well, I may do that at some point, if Chuck and Nancy … don’t agree to the fact that our country has really got problems with crime, with drugs and a lot of other things that come … through our southern border,” Trump said at the Capitol.

“But I’ll tell you, it’s a very bad political issue for the Democrats,” the president contended, though polls show most Americans mostly blame him and congressional Republicans for the shutdown and oppose his proposed border wall.

‘Hang together’

Democratic lawmakers such as House Homeland Security Chairman Bennie Thompson called the shutdown “something [Trump] created, and basically he’s trying to resolve it under the rubric of a national emergency.”

“There’s a general understanding that if he came forward, then based on what it is, it would potentially get tested in the courts,” the Mississippi lawmaker said.

Republican senators emerged from their meeting with Trump saying the president urged them to “just hang together,” as Senate Appropriations Chairman Richard C. Shelby put it. The meeting came after several in the Senate GOP conference — including Susan Collins of Maine, Cory Gardner of Colorado and Lisa Murkowski of Alaska — broke ranks with the president and called on him to seek common ground with Democratic leaders. But Shelby suggested Trump could lose a handful and still win the border battle.

“The overwhelming majority of the caucus will stay together, and that’s all we need,” the Alabama Republican said. “The president is not going to blink, he says. And he shouldn’t. What people should do is come and work out in a rational way the differences.”

North Carolina GOP Rep. Patrick T. McHenry, a former chief deputy whip, predicted support from House Republicans after an emergency declaration “wouldn’t be uniform, but it would be high,” adding, “And it depends on the [Pentagon] accounts you have to take money from in order to fund the wall. That would be the only trepidation a few members would have.”

Georgia GOP Rep. Doug Collins said that if Democrats were going to “lock in and not negotiate at all, I’m not going to take anything [out] of the president’s ability to move this forward.”

‘Petulant president’

Instead of negotiating Wednesday, the two sides traded barbs. While that might energize their conservative and liberal bases, by definition, those fired-up bases will generate pressure for both sides to further dig in. Pelosi dubbed Trump a “petulant president.” House Minority Whip Steve Scalise essentially accused Schumer of lying about the meeting, saying in a frustrated tone that “nobody slammed their hand on a table.”

With no end in sight to the wall standoff, Senate Republican Policy Committee Chairman Roy Blunt suggested expanding the scope of the debate.

The Missouri senator, a senior appropriator, said that counterintuitively expanding the playing field might make it easier to find a way out of the shutdown that Trump might agree to make law.

“One way to make it bigger would be, ‘Let’s talk about next year’s spending numbers as part of this,’” Blunt said.

[Trump threatens he’ll declare national emergency for wall if no deal]

“Let’s get some numbers for next year and even the year after that,” he added. “Let’s not pretend that the Budget Control Act numbers have meaning, because we all know they don’t.”

The budget levels for the upcoming fiscal years under that 2011 budget law are generally considered unworkable.

“This would be a good time to add that to the discussion, which frankly makes the discussion bigger rather than smaller, which might be one of the ways to reach a conclusion,” Blunt said.

But adding a debate about raising the caps would only further complicate what already is a complicated and stalemated negotiation, with neither side in much of a mood to bend.

“It could be fixed tonight,” Shelby said of the partial shutdown. “But I think it’s going to last a while.”

One reason, said House Freedom Caucus Chairman Mark Meadows, is that “both sides are not reading the other side properly,” while also underestimating the other’s resolve to not fold.

“The Democrats think that we’re about ready to fold. … I think that Republicans think that the Democrats are about ready to fold,” the North Carolina Republican said. “And neither of those two things are accurate by any stretch of the imagination.

“You can’t cave. That’s what the Democrats don’t understand,” he said, describing the situation as “all or nothing.”

Jennifer Shutt and Kellie Mejdrich contributed to this report.