A federal judge in Washington on Friday kept in place a hold on President Donald Trump's ban on transgender troops.

In a series of tweets in July, Trump declared that the military will no longer “accept or allow” transgender troops to serve “in any capacity.” Four lawsuits have been filed challenging the ban.

(Related: Trump says military will bar transgender troops.)

In a 31-page ruling, U.S. District Judge Marsha Pechman said that transgender people represent a “protected class.”

“The Court also rules that, because transgender people have long been subjected to systemic oppression and forced to live in silence, they are a protected class,” Pechman wrote. “Therefore, any attempt to exclude them from military service will be looked at with the highest level of care, and will be subject to the Court’s “strict scrutiny.” This means that before Defendants can implement the Ban, they must show that it was sincerely motivated by compelling interests, rather than by prejudice or stereotype, and that it is narrowly tailored to achieve those interests.”

Plaintiffs in the case, nine transgender people who are serving or wish to serve in the military, three groups and the state of Washington, are represented by Lambda Legal and OutServe-SLDN.

Pechman first halted implementation of the ban in a December ruling, saying that the policy “is likely unconstitutional.”

According to the Los Angeles Blade, Pechman refused to issue a permanent injunction, which means the case is likely heading to trial.