US President Donald Trump has lashed out at a federal judge for blocking his policy of sending migrants awaiting US asylum hearings back to Mexico.
“A 9th Circuit judge just ruled that Mexico is too dangerous for migrants,” he tweeted. “So unfair to the US.”
His policy would have returned migrant families to Mexico to await court bids for the right to stay in the US.
It comes as numbers of migrants stopped at the US-Mexico border have surged to the highest level in over a decade.
US immigration officials have estimated border apprehensions in March topped 100,000.
The San Francisco ninth district judge’s order against the migrant policy is not due to go into effect until 12 April, giving US officials a chance to appeal the ruling.
Monday’s court ruling comes as the Department of Homeland Security (DHS), which implements Mr Trump’s immigration directives, is in turmoil following a major shake-up by the administration.
The agency’s Secretary Kirstjen Nielsen quit on Sunday after being summoned to the White House by the president.
Republican Senator Chuck Grassley called on Mr Trump on Monday to halt the leadership purge at the agency.
The senior senator told the Washington Post he is “very, very concerned” about reports of possible further DHS dismissals.
“The president has to have some stability and particularly with the number one issue that he’s made for his campaign,” Mr Grassley said.
“He’s pulling the rug out from the very people that are trying to help him accomplish his goal.”
There are rumours that DHS management undersecretary Claire Grady, now the senior-most Senate-confirmed official in the agency, as well as director of Citizenship and Immigration Services, Lee Francis Cissna, and DHS general counsel, John Mitnick, could be next to go.
Speaking to Fox News on Monday, White House spokesman Hogan Gidley said: “It’s time to do things a little differently.
“The president’s looking around to reshape his team so he can have the people in place to carry out his agenda.”
There are also reports that the president is preparing to toughen his stance on immigration.
According to the New York Times, Mr Trump is also looking to implement further limits on who can seek asylum, end birthright citizenship and close ports of entry at the Mexican border.
Part of Mr Trump’s new agenda will reportedly include implementing a “binary choice” policy.
This would give migrant parents awaiting immigration hearings a choice: agree for their child to be held separately, or be detained together, possibly indefinitely, until their court date.
The White House reportedly envisages the policy as a way to way to end “catch and release”, the longstanding US practice of allowing undocumented immigrants apprehended at the border to continue on their way into the US while they await court hearings.
A 1997 court decision known as the Flores agreement states that immigrant children are only allowed to be held for 20 days.
The Trump administration has reportedly drafted a regulation to change these rules, an official told Axios, so that the government could detain children for longer periods of time.
Senior White House adviser Stephen Miller is said to be egging on the president to adopt an increasingly hardline stance on immigration.
Democratic congresswoman Ilhan Omar on Monday called Mr Miller “a white nationalist” on Twitter.
Meanwhile, amid an ongoing debate about immigration on both sides of the Atlantic, former President Barack Obama told young people at a town hall meeting in Berlin, Germany: “We can’t label everybody disturbed by immigration as racist.”
He also said immigrants should be encouraged to learn the language of their adopted country.