BOSTON — The federal government is urging a judge to throw out a lawsuit seeking monetary damages on behalf of children who were separated from their parents at the U.S.-Mexico border.

U.S. Department of Justice attorneys said in a brief filed Tuesday that Supreme Court precedent bars such a lawsuit for damages on challenges to government policy. They also argue Trump administration officials named in the case are shielded by qualified immunity, among other things.

The federal lawsuit filed in September against then-Attorney General Jeff Sessions and others seeks the creation of a fund to pay for mental health treatment for children who were separated from their parents before the Trump administration agreed to stop the general practice.

The lawsuit filed in Worcester, Massachusetts, says many children continue to suffer psychological impacts of their separation and detention.