A federal judge ruled on Tuesday that US immigration agents could no longer separate immigrant parents and children caught crossing the border from Mexico illegally, and must reunite those families that had been split up in custody.
United States District Court Judge Dana Sabraw granted the American Civil Liberties Union (ACLU) a preliminary injunction in a lawsuit filed over the family separations.
More than 2,300 migrant children were separated from their parents after US President Donald Trump's administration began a "zero tolerance" policy in early May, seeking to prosecute all adults who crossed the border illegally, including those travelling with children.
"The facts set forth before the court portray reactive governance responses to address a chaotic circumstance of the government's own making," Sabraw wrote. "They belie measured and ordered governance, which is central to the concept of due process enshrined in our Constitution."
Sabraw ordered the government to reunite parents with their children younger than 5 years old within 14 days of the order, and children 5 years old and older within 30 days of the order.
Sabraw's ruling could force the administration to rapidly address confusion left by Trump's order, and government agencies to scramble to reunite families. The administration can appeal.
The ACLU had sued on behalf of a mother and her then 6-year-old daughter, who were separated after arriving last November in the United States to seek asylum and escape religious persecution in Democratic Republic of Congo.
While they were reunited in March, the ACLU is pursuing class-action claims on behalf of other immigrants.