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SEATAC, Wash. (CBS/AP) — Pennsylvania and New Jersey are among more than a half-dozen states that plan to sue the Trump administration over a policy of separating immigrant families illegally entering the United States.

“The Trump Administration’s family separation policy is un-American,” said Pennsylvania Attorney General Josh Shapiro. “It violates our core principles and values. The executive order President Trump signed yesterday does not fix this abhorrent policy, and we will not allow this Administration to use children as leverage in political battles.”

In a Twitter post, New Jersey Attorney General Gurbir Grewal said the following: “More than 2,000 children remain separated from their parents, and there’s no apparent plan to reunite them. Yesterday’s executive order falls far short of solving the problems that the President himself created. We will be filing a lawsuit. Our country deserves better.”

Washington Attorney General Bob Ferguson made the announcement Thursday outside a federal prison in the city of SeaTac, south of Seattle, where about 200 immigration detainees have been transferred — including dozens of women separated from their children under the administration’s “zero tolerance” policy. It calls for prosecuting all migrants caught illegally entering the country.

Ferguson said the separations violate the due process rights of children and their parents and that President Donald Trump’s executive order Wednesday halting the practice has not resolved the legal concerns.

“This is a rogue, cruel, and unconstitutional policy,” Ferguson said. “We’re going to put a stop to it.”

The lawsuit would be filed in the U.S. District Court in Seattle.

The states set to join Ferguson’s lawsuit are Massachusetts, California, Maryland, Oregon, New Mexico, Pennsylvania, New Jersey and Minnesota. New York has separately announced plans to sue.

Ferguson has repeatedly challenged the administration, most notably when he successfully sued to block Trump’s initial travel ban against several mostly Muslim countries. It caused chaos at airports when it rolled out in January 2017. A third version of the policy took effect but the U.S. Supreme Court is considering it.

Ferguson and Washington Gov. Jay Inslee expressed alarm after learning last week that U.S. Immigration and Customs Enforcement was transferring some detainees to federal prisons, including dozens of mothers who had been separated from their children to the Federal Detention Center at SeaTac.

“The Trump administration’s new family separation policy is inflicting intentional, gratuitous, and permanent trauma on young children who have done nothing wrong and on parents who often have valid claims for refugee or asylum status,” they wrote in a letter to the administration.

A U.S. 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 2,300 children with their parents.

(© Copyright 2018 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)