The president said illegal immigrants and drugs flowing across the border to Mexico posed a serious security risk, in a televised address to the nation from the Oval Office last night.

He said current levels of illegal immigration posed a “humanitarian crisis”, adding it was “straining public resources”.

He said the “only solution” to end the crisis and re-open the federal government agencies currently shut down would be for the democrats to pass a spending bill with money for the barrier.

The partial federal government shutdown is now in its third week. More than 800,000 federal workers have been working without pay or been sent home since the shutdown began on 22 December.

Trump said: “Illegal immigrants strains public resources. The federal government remains shut down for one reason, and one reason only. Because the Democrats will not fund border security.”

Trump said he had agreed to build a steel barriers, as “requested by the Democrats”, rather than concrete wall as previously planned.  

Trump said he had invited congressional leaders to meet today “to get this done”.

Democrats, who took power of the House of Representatives at the beginning of this year, are opposing in Congress the wall, which Trump promised to build as part of his election campaign.

Trump added during his address that the “border wall would very quickly pay for itself”, as he said the cost to the public purse of illegal drugs “exceeds $500bn a year”. The wall would also be paid for “indirectly” by the US trade deal with Mexico, he said.

The Democrats passed legislation, which would provide funding for government agencies and end the shutdown. But the Republican-led Senate did not approve it because it did not include the $5.7bn for the border wall.

In response to his televised speech, Democrat speaker Nancy Pelosi said her party’s plan would “fund smart, effective border security solutions”.

“But the president is rejecting these bipartisan bills, which would reopen government over his obsession with forcing American taxpayers to waste billions of dollars on an expensive and ineffective wall, a wall he always promised Mexico would pay for,” she added.

Pelosi said: “The fact is, President Trump has chosen to hold hostage critical services for the health, safety and wellbeing of the American people, and withhold the pay cheques of 800,000 innocent workers across the nation, many of them veterans.”

The Democrats have said the wall is “immoral”. With reference to this, Trump said: “The only thing that is immoral is for politicians to do nothing and continue to allow for innocent people to be so horribly victimised [referring to the American population].”

The president has not declared a national emergency, which he had threatened and would have allowed him to pay for the barrier with military funds.

The Trump administration said yesterday it would continue to provide food stamps to poor Americans next month despite the shutdown but said no solution was in place for March, if funding shortfall continues. Roughly 40 million people rely on food stamps in the US.