WASHINGTON — A federal judge in Washington delivered the toughest blow yet to the Trump administration's efforts to phase out an Obama-era program for undocumented immigrants known as "dreamers," ordering the administration to continue the program and accept new applicants for the first time.

U.S. District Judge John Bates called the government's decision to end the Deferred Action for Childhood Arrivals program "virtually unexplained" and therefore "unlawful." However, the judge gave the Trump administration 90 days to provide a more solid reason for ending the program before his ruling will take effect.

In his decision, Bates said the Trump administration's decision to phase out the program starting in March "was arbitrary and capricious because the Department failed adequately to explain its conclusion that the program was unlawful."

If the government does not come up with a better explanation within 90 days, he said, the administration's order to rescind DACA will be vacated and "DHS must accept and process new as well as renewal DACA applications."