A judge in California has ordered US border authorities to reunite separated families within 30 days, setting a hard deadline in a process that has so far yielded uncertainty about when children might again see their parents.

If children are younger than five, they must be reunified within 14 days of the order issued yesterday by US District Judge Dana Sabraw in San Diego Sabraw, an appointee of President George W Bush, also issued a nationwide injunction on future family separations, unless the parent is deemed unfit or doesn't want to be with the child.