SAN FRANCISCO, June 26 (Xinhua) -- Seventeen U.S. states and the District of Columbia on Tuesday filed a lawsuit against the administration of President Donald Trump over its policy forcibly separating children of immigrants from their parents.

Although Trump, amid mounting criticism and global outrage, backed down last Wednesday and signed an executive order ending the separations, Tuesday's complaint with U.S. District Court in Seattle said the policy was "abhorrent and indefensible" and was motivated by "animus and a desire to harm."

Besides the District of Columbia, the litigation is also backed by the states of California, Delaware, Illinois, Iowa, Massachusetts, Maryland, Minnesota, New Jersey, New Mexico, New York, North Carolina, Oregon, Pennsylvania, Rhode Island, Virginia, Vermont and Washington. [ Trump's executive order purported to "maintain family unity, including by detaining alien families together where appropriate and consistent with law and available resources."

The Trump administration's "zero-tolerance" policy on illegal immigration dictates that all immigrants arriving on U.S. shores illegally should be handed in for prosecution and detained under federal custody, and that children traveling with their parents will be sent separately to the U.S. Health and Human Services Department, where they are supervised by other family members, provided with shelter, or sent to foster homes.

"At the same time, we are keeping a very powerful border, and it continues to be a zero tolerance. We have zero tolerance for people who enter our country illegally," Trump said after he signed the executive order.

The legal challenge by the states said until Trump signed the executive order, his zero-tolerance policy "had resulted in the separation of over two thousand children from their parents at the Southwestern border, most recently at a rate of 50-70 families separated every day."

"This unlawful practice exacerbates the trauma already suffered by refugee families while simultaneously artificially increasing illegal entry violations," the complaint read.

Also on Tuesday, the U.S. Supreme Court backed Trump's travel ban targeting citizens of several Muslim-majority nations in a 5-4 vote.

Trump hailed the ruling as "a tremendous victory for the American people and our Constitution," even though it is expected to spark fresh protests and further divide the country.