Immigration authorities have separated about 2,300 children from their parents in recent weeks.

Seventeen states, including Washington, New York and California, sued President Donald Trump’s administration on Tuesday in an effort to force officials to reunite migrant families who have been separated at the US-Mexico border.

The states, all of which are led by Democratic attorneys general, joined Washington, DC, in filing the lawsuit in US District Court in Seattle. It’s the first legal challenge by states over the practice.

“The administration’s practice of separating families is cruel, plain and simple,” New Jersey Attorney General Gurbir Grewal said in an emailed statement.

“Every day, it seems like the administration is issuing new, contradictory policies and relying on new, contradictory justifications. But we can’t forget: the lives of real people hang in the balance.”

Immigration authorities have separated about 2,300 children from their parents in recent weeks, sparking global outrage as images and recordings of weeping children emerged. Many parents are in custody thousands of miles from their children, whom they have not been able to see and have rarely spoken to for a month or more.

After falsely blaming Democrats for the separations and insisting that only Congress could fix the issue, the president last week issued an executive order designed to end the practice under his “zero tolerance” policy, which prosecutes undocumented adults who come to the US.

But the states say his order is riddled with caveats and fails to reunite parents and children who have already been torn apart.

They accuse the administration of denying the parents and children due process; denying the immigrants, many of whom are fleeing gang violence in Central America, their right to seek asylum; and being arbitrary in applying the policy.

A US judge in San Diego is considering whether to issue a nationwide injunction sought by the American Civil Liberties Union that would order the administration to reunite the separated children with their parents.

A Seattle-based immigrant rights group sued on Monday on behalf of held asylum-seekers in Washington state who have been separated from their children.

The states that sued Trump’s administration are: Massachusetts, California, Delaware, Iowa, Illinois, Maryland, Minnesota, New Jersey, New Mexico, New York, North Carolina, Oregon, Pennsylvania, Rhode Island, Vermont, Virginia and Washington.