CHICAGO (CBS) — President Donald Trump has announced the U.S. military will ban transgender individuals from serving “in any capacity.”

In a series of tweets on Wednesday, the president said the military must focus on “decisive and overwhelming victory and cannot be burdened with the tremendous medical costs and disruption that transgender in the military would entail.”

GLAAD — a non-profit LGBTQ advocacy group — denounced the president’s announcement.

“President Trump today issued a direct attack on transgender Americans, and his administration will stop at nothing to implement its anti-LGBTQ ideology within our government — even if it means denying some of our bravest Americans the right to serve and protect our nation,” GLAAD president and CEO Sarah Kate Ellis said. “Today further exposed President Trump’s overall goal to erase LGBTQ Americans from this nation. Trump has never been a friend to LGBTQ Americans, and this action couldn’t make that any more clear.”

GLAAD estimated there are more than 15,000 transgender individuals already serving in the U.S. armed forces.

Equality Illinois, a Chicago-based LGBTQ advocacy group, said the message Trump is sending is “deeply chilling.”

“It is frightening to us to see the language being used being the same language that propped up segregation in the military, that banned women from serving in parts of the military, that kept gay and lesbian soldiers in the closet. I mean, this is sadly drawing on a long and horrific tradition of exclusionary language,” Equality Illinois CEO Brian Johnson said.

Johnson said Trump is turning his back on Americans willing to make the ultimate sacrifice for their country.

The American Civil Liberties Union also blasted Trump’s announcement.

“This is an outrageous and desperate action. The thousands of transgender service members serving on the front lines for this country deserve better than a commander-in-chief who rejects their basic humanity,” ACLU senior staff attorney Joshua Block said. “Let us be clear. This has been studied extensively, and the consensus is clear: There are no cost or military readiness drawbacks associated with allowing trans people to fight for their country. The president is trying to score cheap political points on the backs of military personnel who have put their lives on the line for their country. There is no basis for turning trans people away from our military and the ACLU is examining all of our options on how to fight this. For any trans service member affected by today’s announcement: Please get in touch with us, because we want to hear from you.”

Transgender servicemembers have been able to serve openly in the military since last year, when former Defense Secretary Ash Carter ended a previous ban, declaring it the right thing to do. Since Oct. 1, 2016, transgender troops have been able to receive medical care and start formally changing their gender identifications in the Pentagon’s personnel system.

But Carter also gave the services until July 1 to develop policies to allow people already identifying as transgender to newly join the military, if they meet physical, medical and other standards, and have been stable in their identified genders for 18 months. The military chiefs had said they needed time to study the issue and its effects on the readiness of the force before taking that step.

Last month, military chiefs sought a six-month delay before letting transgender people enlist in their services.

Trump’s announcement of the trandgender military ban came on the 69th anniversary of President Harry Truman signing an executive order ending discrimination in the military based on “race, color, religion or national origin,” and eventually desegregating all branches the armed forces.

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