Donald Trump’s key campaign pledge to build a wall on the US border with Mexico could lead to an American government shutdown, senior US officials have claimed.

Department of Homeland Security Secretary John Kelly told CNN that Mr Trump will “be insistent on the funding” of the wall, which is estimated to cost around $22bn (£17bn).

“It goes without saying that the President has been pretty straightforward about his desire and the need for a border wall so I would suspect – he’ll do the right thing for sure – but I suspect he will be insistent on the funding,” he said.

If Congress does not send Mr Trump a government funding bill by midnight on Friday, the US Government would run out of money and would be forced to shut down.

During Bill Clinton's administration, there were two full government shutdowns during 1995 and 1996 as politicians squabbled over the US budget deficit.

There was also a federal shutdown under Barack Obama as Republicans tried to delay and defund the Affordable Care Act, known as Obamacare, from signed into law.

Mr Trump has requested $1.4bn (£1.09bn) to start the construction of the wall.

But Mick Mulvaney, director of the Office of Management and Budget, told Fox News that Democrats were unwilling to fund the wall as they were angry about Mr Trump’s pick for Supreme Court Justice, conservative-leaning Neil Gorsuch.

When asked if Mr Trump would refuse to sign the funding bill if it did not include money for the wall, Mr Mulvaney replied: “We don’t know yet.”

He added: “No one foresees or wants a shutdown next week.”

US had 'no conversation' with Mexico about paying for Trump's border wall, Rex Tillerson admits

In a separate interview with Bloomberg, Mr Mulvaney revealed that the White House had offered the Democrats to fund $1 in Obamacare subsidies for every $1 towards the border wall, in the hope of reaching a deal before the expiration date.

Democratic Senator Dick Durbin told CNN that if Mr Trump did shut down the government over his “outlandish” proposals, it would be “the height of irresponsibility”.

“He would not want that to define his first 100 days,” he said.

Attorney General Jeff Sessions, who strongly advocates a crack down on immigration, told ABC News that the wall would be paid for “one way or another”, but refused to suggest that its southern neighbour would foot the bill.

Jeff Sessions: Congress will pay for the wall

The Wall Street Journal reported this week that no Congress member who represents districts on the border supports Mr Trump’s plans for the wall, according to a survey which included four Republican senators.

“Build that wall” was one of the rallying cries of Mr Trump’s campaign as he promised to crack down on illegal immigration, drug cartels and to deport convicted criminals.

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He promised that Mexico would pay for the wall, but after he was elected he said the US would pay and Mexico would “reimburse” the US. Mexican President Enrique Pena Nieto has strongly denied the claim, and cancelled his first scheduled trip to meet the President in Washington DC.

The President has long demanded that a “big, beautiful wall”, measuring 30 feet high and made of concrete, be built across the entire border.

Mexican Congressman Braulio Guerra proves Trump’s border wall is ‘absurd’ by climbing it

But Mr Kelly admitted earlier this month that it was unlikely the wall would stretch “from sea to shining sea”, and said he could not provide a cost estimate – although a revealed DHS memo reported $22bn.

“There is no way I can give the committee an estimate of how much it will cost,” Mr Kelly said at an April hearing of the Senate Homeland Security and Governmental Affairs Committee.

“I don’t know what it will be made of, I don’t know how high it will be, I don’t know if it’s going to have solar panels on its side and what the one side is going to look like and how it’s going to be painted,” he said.

In June 2015, the President accused Mexicans of being “drug dealers” and “rapists” to justify the project, which landed him in hot water on the first day of his campaign.