A new US government shutdown looks increasingly likely as negotiations reached an impasse on whether to limit the number of undocumented immigrants that can be detained.

The two sides also remain separated on how much spending to allocate for president Donald Trump‘s promised border wall.

With a deadline of Friday approaching, talks between Democrat and Republican negotiators stalled over a dispute about curbing the number of immigrants that can be detained by Immigration and Customs Enforcement (ICE).

Republicans have said they don’t want that cap to apply to immigrants caught committing crimes, but Democrats do.

Mr Trump used the dispute to cast the Democrats as being soft on criminals. ”I don’t think the Dems on the Border Committee are being allowed by their leaders to make a deal. They are offering very little money for the desperately needed Border Wall & now, out of the blue, want a cap on convicted violent felons to be held in detention!” he tweeted on Sunday.

Trump shuts down US government over Mexico border wall – in pictures Show all 15 1 /15 Trump shuts down US government over Mexico border wall – in pictures Trump shuts down US government over Mexico border wall – in pictures Federal workers and contractors rally against the partial federal government shutdown Getty Images Trump shuts down US government over Mexico border wall – in pictures The US Capitol on the first morning of a partial government shutdown in Washington EPA Trump shuts down US government over Mexico border wall – in pictures Federal workers and contractors rally against the partial federal government shutdown Getty Trump shuts down US government over Mexico border wall – in pictures President Trump speaks with children who called the North American Aerospace Defense Command Santa tracker in the State Dining Room of the White House. He earlier in the day, tweeted that he was 'all alone in the White House' waiting for Democrats to make a deal on border security EPA Trump shuts down US government over Mexico border wall – in pictures Furloughed federal workers pick up free food at a pop-up store of Kraft Heinz Getty Images Trump shuts down US government over Mexico border wall – in pictures Hundreds of federal workers and contractors rally against the partial federal government shutdown Getty Trump shuts down US government over Mexico border wall – in pictures A pedestrian walk past the U.S. Capitol ahead of a possible partial government shut down in Washington, U.S., December 20, 2018. REUTERS/Joshua Roberts JOSHUA ROBERTS Reuters Trump shuts down US government over Mexico border wall – in pictures From left, House Majority Leader Steny Hoyer, Senate Minority Leader Chuck Schumer, Sen. Dick Durbin and Speaker of the House Nancy Pelosi walk to speak to reporters after meeting with President Donald Trump about border security in the Situation Room of the White House. Trump declared he could keep parts of the government shut down for "months or even years" as he and Democratic leaders failed in a second closed-door meeting to resolve his demand for billions of dollars for a border wall with Mexico Evan Vucci AP Trump shuts down US government over Mexico border wall – in pictures Federal workers and contractors rally against the partial federal government shutdown Getty Images Trump shuts down US government over Mexico border wall – in pictures A sign alerts visitors to the closure of the National Archives on the fifth day of a partial government shutdown EPA Trump shuts down US government over Mexico border wall – in pictures Hundreds of federal workers and contractors rally against the partial federal government shutdown Getty Images Trump shuts down US government over Mexico border wall – in pictures Visitors read signs announcing the closure of the White House Visitor Center EPA Trump shuts down US government over Mexico border wall – in pictures President Donald Trump speaks during a round-table discussion on border security and safe communities with State, local, and community leaders in the Cabinet Room of the White House Getty Images Trump shuts down US government over Mexico border wall – in pictures A sign alerts visitors to the closure of the White House Visitor Center on the first day of a partial government shutdown EPA Trump shuts down US government over Mexico border wall – in pictures Furloughed federal workers show their IDs for entering a pop-up store of Kraft Heinz Getty Images

Democrats say they proposed their cap to force ICE to concentrate its internal enforcement efforts on dangerous immigrants, not those who lack legal authority to be in the country but are productive and otherwise pose no threat.

They have proposed reducing the current number of beds ICE uses to detain illegal immigrants from 40,520 to 35,520, and to limit the number for illegal immigrants caught within the US to 16,500.

Acting White House chief of staff Mick Mulvaney, in appearances on NBC’s Meet the Press and Fox News Sunday, said “you absolutely cannot” eliminate the possibility of another shutdown if a deal is not reached over the wall and other border matters.

The White House had asked for $5.7bn (£4.4bn), a figure rejected by the Democratic-controlled House.

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“I think talks are stalled right now,” Republican senator Richard Shelby said on Fox News Sunday. ‘’I’m not confident we’re going to get there.”

Senator Jon Tester, who appeared on the same programme, agreed: “We are not to the point where we can announce a deal.”

The last government shutdown was the longest in US history, stretching on for 35 days, leaving more than 800,000 government workers without pay and forcing a postponement of the State of the Union address.