MIAMI (AP) — U.S. immigration authorities illegally kept more than $300 million in bond payments from tens of thousands of low-income immigrant families and U.S. citizens, according to a lawsuit filed Tuesday.

U.S. Immigration and Customs Enforcement kept the money for so long that $240 million was transferred to a U.S. Treasury account for unclaimed funds, said Motley Rice LLC, one of the firms that filed the lawsuit in federal court for the Eastern District of New York.