By Frank Pallotta

(CNN) -- Two of the biggest voices in the transgender community are speaking out against President Trump's plan to reinstate a ban on transgender individuals from serving in the U.S. armed forces.

Caitlyn Jenner and Laverne Cox took to social media on Wednesday to condemn Trump's announcement.

"There are 15,000 patriotic transgender Americans in the U.S. military fighting for all of us," Jenner tweeted. "What happened to your promise to fight for them?"

Jenner referenced a tweet Trump wrote as a candidate for president in which he promised to "fight for" LGBTQ people.

Jenner, who said she voted for Trump, told CNN in April that the president "has made some mistakes" regarding his positions on some LGBTQ issues.

"I don't support him in everything that he does," Jenner said. "But we needed to shake the system up."

In a tweet, Cox, who stars in "Orange is the New Black" and advocates for transgender rights, thanked "trans folks currently serving in the military" for their service.

"Marginalized folks have often found ourselves at odds with systems which seek to subjugate & erase us," she wrote. "Let us love each other more & fight."

"Your lives, safety, & service matter," she tweeted with the hashtag, "#TransIsBeautiful."

In a statement to CNN, Cox added that she has met with many transgender service members to discuss their experiences.

"I have heard from them humiliating stories of being misgendered and experiencing various kinds of mistreatment when they are willing to put their lives on the line in ways many of us would never do, including our current president," Cox said in the statement.

"This latest reversal of another Obama administration policy continues to send the message to trans Americans that our lives, our safety and service are less valuable and unwanted in this country, the country I love and hold so dear," she said. "Let's all come together and send the message to trans Americans that despite what this president and administration proclaims that trans lives, safety and service are valuable, that they matter."