The court order on late Tuesday asked federal officials to stop detaining parents apart from their minor children, absent a determination the parent is unfit or the parent declines reunification; reunify all parents with their children under the age of 5 within 14 days and reunify all parents with their children age 5 and older within 30 days.
The order by federal judge of the court in San Diego (California), Dana Sabraw, also mandated that officials let parents contact their children by phone within 10 days, if the parent is not already in contact with his or her child, CNN reported.
Since the US started in April its controversial "zero tolerance" strategy against immigration -- that was suspended last week over strong criticism from several quarters -- the government led by President Donald Trump separated 2,575 minors from their parents at the Mexico border.
Sabraw's verdict came in response to a lawsuit filed by the American Civil Liberties Union on behalf of two women, one from Congo, who was separated from her seven-year-old daughter, and the other from Brazil, who was separated from her 14-year-old son.
The judge also suspended the deportation of parents, who remained separated from their children. The judge described the separation of families as a "chaotic circumstance of the government's own making".
Sabraw's decision could help clear the confusion created by an order issued last week by Trump to stop separation of families at the border, but without clear instructions about how to reunite them.
The government's decision to suspend separation of families had come after global outrage over images of children being imprisoned in different facilities, often resembling cages.