US President Donald Trump says he will allow the federal government to shut down if Democrats refuse to back his demand for a wall at the Mexican border and other major changes to immigration laws his administration wants.
"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!" Trump said on Twitter.
The Republican president has used the threat of a government shutdown several times since taking office in 2017 in a bid to get his priorities in congressional spending bills, especially funding for a wall along the southern US border.
A disruption in federal government operations in the months before November congressional elections could backfire on Trump if voters blame Republicans, who control Congress, for the interruption in services.
Trump wants Congress to pass legislation that addresses immigration issues, including the border wall, changing the way visas are allotted and other immigration restrictions.
Although Republicans control Congress, disagreements between moderates and conservatives in the party have impeded a speedy legislative fix.
Stand-offs over spending levels and immigration led to a three-day government shutdown, mostly over a weekend, in January and an hours-long shutdown in February.
The Republican president has made tougher immigration laws a centrepiece of his administration, from the first ill-fated travel ban on people from predominantly Muslim nations to the current battle raging over the separation of illegal immigrant children from their parents at the US-Mexico border.
A federal judge on Friday urged the government to focus on finding deported immigrant parents so it could reunite them with their children who remain in the United States.
Trump has requested $25 billion (A$33.8b) to build the border wall and $1.6 billion has already appropriated for the project.
Interfaith Welcome Coalition volunteers assist a Honduran family at the Greyhound Bus station in San Antonio. Source: AAP
