U.S. army soldiers are seen marching in the St. Patrick's Day Parade in New York, March 16, 2013. REUTERS/Carlo Allegri

A United States court on Monday ruled the Trump administration could not enforce an updated policy barring certain transgender people from serving in the U.S. military, becoming the second court in the country to rule against the government since it unveiled the policy in March.

President Donald Trump announced on March 23 that he would endorse a plan by Defense Secretary Jim Mattis to restrict the military service of transgender people who experience a condition called gender dysphoria. The policy replaced an outright ban on transgender service members that Trump announced last year on Twitter, citing concern over military focus and medical costs.

U.S. District Judge Colleen Kollar-Kotelly in Washington denied a request by the administration to lift an injunction she had issued against Trump's original ban.

Her ruling follows one by a federal judge in Seattle who in April also refused to allow the new policy to go into effect. The government has appealed that ruling to the San Francisco-based 9th U.S. Circuit Court of Appeals.

The administration argued that the new policy, which also bars anyone who requires or has undergone gender transition, was no longer a categorical ban.

Kollar-Kotelly disagreed. The new policy effectively implements the original ban "by targeting proxies of transgender status, such as 'gender dysphoria' and 'gender transition,' and by requiring all service members to serve 'in their biological sex,'" she wrote in Monday's ruling.

The U.S. Department of Justice declined to comment.

The American Psychiatric Association defines gender dysphoria as a "clinically significant distress" due to a conflict between a person's gender identity and their sex assigned at birth. Not all transgender people suffer from gender dysphoria, according to the association, which opposes the military ban.

Monday's ruling came in a lawsuit filed last August by several aspiring service troops and current members of the U.S. Army, Air Force and Coast Guard. Last October, Kollar-Kotelly ruled that the original ban likely violated the U.S. Constitution's guarantee of equal protection under the law.

Three more judges also blocked the ban, forcing the military to permit openly transgenderindividuals to join the ranks.

Trump's ban reversed Democratic former President Barack Obama's policy of allowingtransgender troops to serve openly and receive medical care to transition genders.

The new Trump policy exempts those diagnosed with gender dysphoria during the Obama policy, allowing them to remain in the military and serve according to their gender identity.