On a call with reporters on Saturday, White House officials said President Donald Trump still plans on having Mexico pay for a wall along the US-Mexico border.

The statement comes on the first day of a partial shutdown of the federal government, after Congress adjourned without agreeing on a spending deal.

Trump has promised that Mexico would pay for the wall's construction since the early days of his presidential campaign, but has gradually begun changing the details of a hypothetical arrangement.

Senior Trump administration officials said Saturday that the president still plans on having Mexico pay for a wall along the US-Mexico border.

The statement comes on the first day of a partial shutdown of the federal government, after Congress adjourned until December 27 without agreeing on a spending deal.

President Donald Trump made a last-minute decision in recent days to demand that Congress allocated $5 billion for the wall, despite years of promises that Mexico would foot the bill.

"Our administration continues to believe that [Mexico] will [pay for the wall]," a senior administration official said told reporters on a background call about the shutdown. "This debate is about ensuring that we have the appropriations to get the wall built."

The official said the US planned to initially bear the wall's construction costs so there would be no "wait on negotiations with Mexico," and the administration would "be able to move on constructing the wall."

The official continued: "What this debate is is fundamentally about getting started."

Read more: Trump tweeted a design for 'steel slats' along the border with spikes on top — and called it 'totally effective while at the same time beautiful'

Senate Minority Leader Chuck Schumer is met by reporters as he arrives at the Capitol on the first morning of a partial government shutdown, in Washington, Saturday, Dec. 22, 2018. Associated Press/J. Scott Applewhite

Senate Democrats have frequently seized on the Trump administration's promises that Mexico would pay as evidence that Congress shouldn't have to supply the funding. Senate Minority Leader Chuck Schumer said Saturday that the shutdown occurred "because of one person and one person alone — President Trump."

He continued: "We arrived at this moment because the president has been on a destructive two-week temper tantrum demanding the American taxpayer pony up for an expensive, ineffective border wall that the president promised Mexico would pay for."

Trump's latest pitch for Mexico's responsibility for the wall came in a tweet Wednesday, where he connected the wall's cost to the newest North American trade pact, the US-Mexico-Canada Agreement (USMCA).

Though the USMCA was signed by the countries' leaders last month, it hasn't yet been ratified by Congress, or Mexico or Canada's legislative bodies.

When White House press secretary Sarah Huckabee Sanders was asked about the deal last week, she said the administration thought that more than $25 billion would flow into the Treasury, though she didn't elaborate on the calculation.

Trump has promised since his election that Mexico would pay

"I would build a great wall, and nobody builds walls better than me, believe me, and I’ll build them very inexpensively," Trump said in his June 2015 presidential announcement speech. "I will build a great, great wall on our southern border and I’ll have Mexico pay for that wall."

The Mexican government has repeatedly said the country will not pay for the wall.

By January 2017, Trump had pared back his plan to a version closer to his current pitch, saying Mexico would pay back the cost of construction for "the Great Wall."

During the campaign, Trump estimated the wall would cost between $8 billion and $12 billion to build.

But on January 8, 2018, the Trump administration was expected to request $18 billion from Congress for the wall. Two weeks later, Trump introduced a new immigration bill that included a request for $25 billion towards the wall.

Amid these proposals, Trump also tweeted that the wall would cost $20 billion.

More recently, Trump has fallen back on the argument that the wall would essentially pay for itself through the increased economic output stemming from the USMCA. He has doubled down on that claim multiple times in recent weeks.

In a fiery White House meeting between Trump and top Democrats on December 11, House Speaker-designate Nancy Pelosi and Senate Minority Leader Chuck Schumer dismissed Trump's suggestion that the USMCA's benefits would make up for the wall funding.

Business Insider's Bob Bryan reported that Pelosi later told Democrats that she told Trump that dedicating money to a wall would still mean Americans were losing out on the benefits.

"I said, 'You're going to take the money we made from the trade agreement. Well that's an opportunity cost, Mr. President, for American workers and our economy that's supposed to benefit from that. They did not know you are passing a bill so that you could pay for a wall and say Mexico paid for it with our profits from our workers and our businesses and the rest,'" Pelosi reportedly said.