Fifteen US states and the District of Columbia have filed a lawsuit in New York challenging President Donald Trump's plan to end a programme protecting young immigrants from deportation.
The suit was first announced by Washington state Attorney General Bob Ferguson, who called Mr Trump's act "a dark time for our country".
Plaintiffs include New York, Massachusetts, Washington, Connecticut, Delaware, District of Columbia, Hawaii, Illinois, Iowa, New Mexico, North Carolina, Oregon, Pennsylvania, Rhode Island, Vermont and Virginia.
On Tuesday, US Attorney General Jeff Sessions said the programme, known as the Deferred Action for Childhood Arrivals or DACA, will end in six months to give Congress time to find a legislative solution for the immigrants.
The participants were brought to the US illegally as children or came with families who overstayed visas.
Those already enrolled in DACA remain covered until their permits expire.
If their permits expire before March 5 2018, they are eligible to renew them for another two years as long as they apply by October 5.
However, the programme is not accepting new applications.
Opponents of the programme said they are pleased with the Trump administration's decision.
They called DACA an unconstitutional abuse of executive power, but proponents of the programme said the move by Mr Trump was cruel.
Mr Ferguson said the action violates the due process rights of the immigrants.
He said he fears the information the immigrants provided to the government to participate in DACA could be used against them.
"It's outrageous, it's not right," an emotional Mr Ferguson said at a news conference in Seattle.
"As attorney general for the state of Washington, I have a hammer, it's the law."
Washington Governor Jay Inslee joined Mr Ferguson at the news conference and said "this is one more of a long train of abuses that this president has attempted to foist on this great nation".
Earlier this year, Mr Ferguson sued Mr Trump over the initial travel ban, which resulted in a federal judge blocking nationwide enforcement.