Donald Trump's administration has announced it is shutting down a programme that protected from deportation hundreds of thousands of young immigrants who were illegally brought into the country as children.
The Deferred Action for Childhood Arrivals (DACA) initiative, introduced under President Barack Obama, has given nearly 800,000 young immigrants a reprieve from deportation and the ability to work legally in the form of two-year, renewable work permits.
Under the plan announced on Tuesday, the Trump administration will stop considering new applications for legal status, but will allow any DACA recipients with a permit set to expire before March 5, 2018, the opportunity to apply for a two-year renewal.
The administration is giving Congress six months to come up with an alternative before the Government stops renewing permits for people already covered.
Mr Trump defended his decision to phase out the program, saying in a statement he is "not going to just cut DACA off, but rather provide a window of opportunity for Congress to finally act".
Former President Barack Obama said Mr Trump's decision to roll back the program is "cruel" and "self-defeating".
"This action is contrary to our spirit and to our common sense," Mr Obama said in a statement posted to Facebook.
"Ultimately, this is about basic decency.
"This is about whether we are a people who kick hopeful young strivers out of America"
Making the announcement to the press, Attorney General Jeff Sessions said that America needs to have a lawful immigration that “serves the national interest” and the US cannot admit everyone who wants to come to the country.
"It is my duty to ensure that the laws of the United States are enforced and that the constitutional order is upheld," Mr Sessions.
"Such an open-ended circumvention of immigration laws was an unconstitutional executive overreach of authority by the executive branch."
President Obama created DACA through an executive order in 2012 for people without serious criminal histories who were younger than 16 when they came to the US before 2007.
Republican House Speaker Paul Ryan said DACA was "a clear abuse of executive authority" and never a "viable long-term solution".
Mr Ryan said: "It is my hope that the House and Senate, with the president's leadership, will be able to find consensus on a permanent legislative solution that includes ensuring that those who have done nothing wrong can still contribute as a valued part of this great country."
Senior Democrats immediately condemned the announcement, with Nancy Pelosi calling it "a deeply shameful act of political cowardice and a despicable assault on innocent young people".
Former Republican presidential candidate John McCain also opposed the move, saying it was "the wrong approach to immigration policy".
"I strongly believe that children who were illegally brought into this country through no fault of their own should not be forced to return to a country they do not know," Senator McCain said.