Washington (CNN) A coalition of 18 attorneys general filed a lawsuit on Tuesday over the Trump administration's separation of undocumented children and parents at the border.

The lawsuit argues that the practice of family separations is "irrationally discriminatory" and violates the constitutional guarantee of equal protection "because it targets only people crossing our southwestern border, the majority of whom are from Latin America, and not anyone crossing the northern border or entering the United States elsewhere," according to a news release from New York Attorney General Barbara Underwood's office.

The lawsuit , filed in the US District Court for the Western District of Washington, is brought by the attorneys general of California, Delaware, the District of Columbia, Illinois, Iowa, Maryland, Massachusetts, Minnesota, New Jersey, New Mexico, New York, North Carolina, Oregon, Pennsylvania, Rhode Island, Vermont, Virginia and Washington state. All of them are Democrats.

in the separation of migrant families. President Donald Trump Democrats have harshly criticized the Trump administration's "zero tolerance" policy, which has resultedin the separation of migrant families. President Donald Trump signed an executive order last week that he said would help stop the separation of undocumented families at the border after an intense backlash over the practice.

"What he (the President) is doing with families on the border, separating children, violates the Constitution," New York Gov. Andrew Cuomo told CNN's Wolf Blitzer earlier on Tuesday. "Our position is it violates the Constitution, violates due process, violates equal protection and violates the Administrative Procedure Act."

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