US President Donald Trump has lashed out at a judge for blocking his policy of sending asylum seekers to Mexico to await court hearings in their cases.
His policy would have returned migrant families back over the border as they seek a legal right to stay in the US.
The legal defeat comes as migrant numbers at the US-Mexico border surged to their highest since 2008.
Mr Trump was said to be livid after US immigration officials estimated border apprehensions in March had topped 100,000.
The San Francisco ninth district judge's order, on Monday against the migrant policy is not due to go into effect until this Friday, giving US officials a chance to appeal.