Irritated at the stalling of his border wall plans, US President Donald Trump has threatened to “shut down” the government in his latest tweet taking aim at Democrats over immigration reform.

The Sunday morning tirade saw the president claim he “would be willing to ‘shut down’” the federal government if members of Congress from the opposition party didn’t row in behind Republicans in voting for his immigration reform package, which includes releasing funds for the US-Mexico border wall that formed the cornerstone of his election campaign.

“I would be willing to ‘shut down’ government if the Democrats do not give us the votes for Border Security,” the president tweeted, “which includes the Wall! Must get rid of Lottery, Catch & Release etc.”

I would be willing to “shut down” government if the Democrats do not give us the votes for Border Security, which includes the Wall! Must get rid of Lottery, Catch & Release etc. and finally go to system of Immigration based on MERIT! We need great people coming into our Country! — Donald J. Trump (@realDonaldTrump) July 29, 2018

He also called for an immigration system “based on MERIT!,” adding that immigrants wanted by the USA needed to be “great people.”

READ MORE: Troops on Mexican border can’t enforce immigration laws – California governor

Trump's criticism comes two weeks after a federal court order forced the administration to stall its controversial practice of separating the children of migrant families caught along the border.

While 1,800 children previously separated have since been reunited with parents and sponsors in the last several days, hundreds more remain separated.

Earlier this year, the federal government experienced two shutdowns in the space of three weeks. The first came over a failed deal for Dreamers – the illegal migrants who came to the US as children – while the second lasted several hours after a successful filibuster by Republican Rand Paul stalled a Senate vote passing budget legislation

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