A federal judge on Monday barred President Donald Trump's administration from proceeding with plans to exclude transgender people from military service.

U.S. District Judge Colleen Kollar-Kotelly ruled that the transgender service members who had sued over Trump's policy were likely to win their lawsuit. She directed a return to the situation that existed before Trump announced his new policy this summer, saying the administration had provided no solid evidence for why a ban should be implemented.

Trump had ordered a reinstatement of the longstanding policy that barred transgender individuals from joining the military; service members who were revealed to be transgender were subject to discharge. Under President Barack Obama, that policy was changed last year to allow transgender people to serve openly.

The Trump administration may appeal Kollar-Kotelly's decision, but for now, the proposed ban remains unenforceable under Kollar-Kotelly's preliminary injunction.

"We disagree with the court's ruling and are currently evaluating the next steps," said Justice Department spokesman Lauren Ehrsam.

She reiterated the department's view that the lawsuit was premature because the Pentagon was still in the process of reviewing how the transgender policy might evolve.

One of the attorneys handling the lawsuit, Shannon Minter of the National Center for Lesbian Rights, said the ruling was an enormous relief to his clients.