With time dwindling before a new Congress is sworn in, Donald Trump refused to budge in his demand for billions in funding for a border wall, narrowing prospects for a government shutdown to end when the legislature reconvenes.
His claim that Democrats are to blame for the deaths of migrant children in US custody, meanwhile, sparked a nasty political controversy.
Democrats will take control of the House of Representatives on 3 January. Through the weekend, Trump stuck to his strategy of trying to foist blame for the shutdown, now in its ninth day, on the opposition party.
Senior White House adviser Kellyanne Conway said the president was waiting for Democrats to negotiate. Democrats have accused Trump of derailing government in a misguided effort to advance a pet policy.
Amidst criticism that Trump has not spoken to the incoming speaker, Nancy Pelosi, since 11 December, Conway told CNN's State of the Union the president was "in the White House. He's in Washington ready to negotiate."
Trump noted on Twitter on Saturday that his border wall plan has failed to gain the support it needs: of at least 10 Democrats in the Senate.
"Now we have to do it the hard way, with a Shutdown," Trump wrote, seemingly adding fuel to Democratic claims that he is to blame. In that last meeting with Pelosi, and Senate minority leader Chuck Schumer, the president said he would be proud to force a shutdown over the issue of the wall.
Most voters appear to be aligned with Democrats, who when not pointing to Trump's campaign promise that Mexico would pay for the wall, contend that there is little need for it. At least 56% of Americans oppose Trump's idea, according to a Harvard CAPS/Harris poll released on Friday. Democrats won overwhelming victories in the November midterm elections by opposing Trump's immigration proposals.
Members of Trump's inner circle have admitted as much, with outgoing chief of staff John Kelly saying in an interview published on Sunday the proposal for increased border security was "not a wall".
Controversially, Trump has blamed the deaths of migrant children in US custody on Democrats, tweeting on Saturday that "any deaths of children or others at the Border are strictly the fault of the Democrats and their pathetic immigration policies".
Two Guatemalan children have died in US custody this month. The circumstances and causes of their deaths remain unclear and disputed.
Amid criticism of the president, Conway sought to turn the tables, telling CNN: "I don't like some of these Democrats using these deaths as political pawns."
She added: "The president does not want these children taking these perilous journeys. Some of them are paying the ultimate price."
Former Virginia governor Terry McAuliffe, a Democrat openly considering a White House run in 2020, told CNN the president's reaction to the deaths of the children was inexcusable, calling it "the lowest act I have ever seen [from] any president in the history of this country".
On ABC's This Week, commissioner of US Customs and Border Protection Kevin McAleenan said the deaths of the two children were "absolutely devastating".
"Our agents did everything they could, as soon as these children manifested symptoms of illness, to save their lives," McAleenan said.
Asked if the federal government bore any responsibility for the children's deaths. He said he thought it was "a multi-faceted problem that requires a multi-faceted solution". He also called the situation at the border a "humanitarian crisis" and said children were "coming through a system built for adults who are violators of the law".
"What we've done immediately," he said, "is that we do medical checks of children, 17 and under, as they come into our process. That's not a capacity we've had."
McAleenan spoke positively of state department aid to central American countries, with whom he said the US should work to tackle the problem. In a Friday tweet, Trump threatened to cut off such aid to Honduras, Guatemala and El Salvador.
To end the shutdown, Trump could agree to sign some version of a spending bill passed before the Christmas holiday by the Republicans in the Senate. It did not supply the $5bn in funding for a wall that he has since demanded.
Speaking to CNN, South Carolina senator Lindsey Graham speculated that Democrats might be willing to concede some "wall-slash-border security funding" in exchange for Republican concessions on protections for undocumented US residents who arrived as children.
"There will never be a deal without wall funding," Graham said.
While the shutdown goes on, hundreds of thousands of federal workers remain without pay, either on duty or forcibly off it and facing increasing hardship. Key functions at agencies tasked with stewardship of the environment, agriculture and other sectors are also beginning to be affected.
This week, Trump claimed without evidence that most workers affected by the shutdown "are Democrats".