Donald Trump may be ready to compromise to win funding for a wall on the Mexico border, with his chief of staff suggesting it does not have to be concrete.
Mick Mulvaney has indicated the US president may accept a "steel fence" in order to break the continuing stalemate in Washington DC.
Mr Trump is trying to convince the Democrats to approve around $5bn (£3.95bn) to build the wall, which he says is vital to stop illegal immigrants and criminals entering the US.
The stalemate between the two sides has led to a shutdown of some government departments, with around 800,000 employees off work without pay, and Mr Trump threatening to keep it going for "months or even years".
He has also said he is considering declaring a national emergency so he could bypass US Congress and get the funding.
But hinting at a possible compromise, Mr Mulvaney told US TV show Meet the Press: "If he has to give up a concrete wall, replace it with a steel fence in order to do that so that Democrats can say, 'See? He's not building a wall anymore,' that should help us move in the right direction."
The president has previously suggested his definition of "wall" is flexible, but Democrats view the whole idea as immoral and ineffective, and prefer other forms of border security.
Mr Trump campaigned for on a promise to make Mexico pay for the barrier but, predictably, America's southern neighbour refused.
Talks to end the government shutdown – led by Vice President Mike Pence – again ended without a breakthrough on Saturday.
The president meanwhile continued to press his case on Twitter, posting an image of a barrier alongside the caption "The wall is coming" – a reference to the tagline from hit TV show Game of Thrones.
He added: "V.P. Mike Pence and team just left the White House. Briefed me on their meeting with the Schumer/Pelosi representatives. Not much headway made today. Second meeting set for tomorrow. After so many decades, must finally and permanently fix the problems on the Southern Border!"
Nancy Pelosi, speaker of the House of Representatives, has said Democrats will start approving individual bills to reopen government departments, starting with the Treasury, so Americans could get their tax refunds.
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"While President Trump threatens to keep the government shut down for 'years', Democrats are taking immediate further action to re-open government, so that we can meet the needs of the American people, protect our borders and respect our workers," Ms Pelosi said.
Democrats now hold the balance of power in the house after it reconvened this week with a record number of women taking up seats following the midterm elections.