By Kate Davidson and Kristina Peterson 

Negotiations over a bipartisan deal for border-security funding have stalled, aides familiar with the talks and other officials said, raising the specter of another government shutdown at the end of this week.

The snag in talks heightened prospects that President Trump will declare a national emergency and seek to divert funds into constructing a wall along the Mexican border.

Mick Mulvaney, Mr. Trump's interim chief of staff, on Sunday said the possibility of the second lapse in government operations couldn't be ruled out.

"Is a shutdown entirely off the table? The answer is 'no,' " Mr. Mulvaney said on NBC. A presidential emergency declaration to build the border wall is "absolutely on the table," he said.

Such a declaration, to which lawmakers from both parties have expressed opposition, would likely face an immediate court battle.

The government's funding expires at 12:01 a.m. on Saturday. Aides said they expected the talks to resume well before then. Lawmakers often haggle up until the last minute in an effort to cut the most advantageous deal possible.

The impasse, which occurred before participants had finalized border-security funding levels, pointed to the likely difficulty of talks over the coming five days.

Adding to this week's task, lawmakers also need to wrap up details of a broader budget agreement to fund nine of 15 federal agencies through the rest of the fiscal year, which ends Sept. 30.

Those agencies, including the Justice, State, Treasury and Interior departments, are currently being funded by a short-term spending bill that lawmakers agreed to in January to end a 35-day government shutdown.

If Congress doesn't reach agreement by the end of the day on Friday, those agencies likely would shut down again, triggering a new round of furloughs for hundreds of thousands of federal workers and disrupting services across the government.

Mr. Trump, who had said publicly he would accept political responsibility before the 35-day partial government shutdown began in December, blamed Democrats for the prospect of another one. He wrote in a Twitter post that last week was "a very bad week for Democrats," pointing to strong economic data, his State of the Union address and the controversy surrounding Democratic officials in Virginia. "I actually believe they want a Shutdown. They want a new subject!"

The talks this weekend snagged over the issue of how many detention beds would be provided at the border for people detained by Immigration and Customs Enforcement officials. Democrats have been seeking to limit the number of beds in exchange for meeting GOP demands to build more physical barriers along the border. Republicans, however, wanted exceptions to the limits.

Democrats had proposed establishing a new limit on detention beds used by ICE officials when apprehending people for violations within the U.S., known as interior enforcement. Those beds would be capped at 16,500, within the existing overall cap of 40,520 beds funded in the fiscal year 2018 spending bill.

"A cap on ICE detention beds will force the Trump administration to prioritize deportation for criminals and people who pose real security threats, not law-abiding immigrants who are contributing to our country, " said Rep. Lucille Roybal-Allard (D., Calif.), who leads the House Appropriations Homeland Security panel.

Republicans objected, wanting to exclude violent criminals from that cap. Without an agreement on ICE beds, talks on funding levels and physical barriers stalled. It wasn't clear when the discussions would resume, a senior GOP aide said.

The stall in the talks also meant negotiators hadn't reached any agreement on funding for the barrier along the Southern border. "We hit a snag here that prevented us from even getting to that," the senior GOP aide said.

On Sunday, Sen. Jon Tester, a Montana Democrat who is involved in the talks, said on Fox News, "Negotiations seldom go smooth, all the way through. It's give and take. It's compromise."

He said he wasn't certain negotiators would reach a deal. "But this group of people and the folks from the House, I think we're going to end up with something that deals with detention beds, with barriers, with technology, with the challenges we have in the Southern border in a common-sense way."

Mr. Mulvaney said Mr. Trump remained committed to building the wall "with or without Congress" as lawmakers negotiated a proposal in the range of $1.3 billion to $2 billion that would include funding for barriers and other measures.

One senior White House official on Saturday said the current talks for wall funding were "nowhere close" to $2 billion, and expressed pessimism about reaching a deal this week.

The amount under negotiation is well short of Mr. Trump's demands of $5.7 billion, but could mark an increase from the $1.3 billion that was allocated for border security in fiscal 2018.

Sen. Chris Murphy (D., Conn.), said Democrats would be willing to compromise over some funding for the wall, noting that many of them have previously voted for border security. "I think the problem now is that we've only got about seven months left on the fiscal year, so I don't think the president can actually spend much more than $2 billion," he said on CNN.

Mr. Mulvaney declined on Sunday to specify an amount of funding that Mr. Trump would find sufficient to sign a bill into law. "The president is going to build the wall," he said. "We'll take as much money as you can give us and then we will find the money someplace else, legally, to secure that Southern barrier. This is going to get built with or without Congress."

Rep. Liz Cheney (R., Wyo.), the chairwoman of the House GOP conference, said she is hopeful the group negotiating over border security would reach an agreement, but stopped short of saying whether Republicans would agree to a potential compromise for a lower amount than Mr. Trump had demanded for border-wall funding.

"It's going to have to be sufficient funds through an agreement hopefully that we can reach that will enable us to know that moving forward we'll be able to have a wall, have a barrier, on those parts of the border where it's really necessary," she said on CNN.

--Natalie Andrews and Michael C. Bender contributed to this article.

Write to Kate Davidson at kate.davidson@wsj.com and Kristina Peterson at kristina.peterson@wsj.com

(END) Dow Jones Newswires

February 10, 2019 19:08 ET (00:08 GMT)