The United States military has expanded its equal opportunity policy to include sexual orientation, Defense Secretary Ash Carter announced Tuesday. Carter revealed the news while giving the keynote address at the Pentagon's LGBT Pride Month Ceremony and followed it by saying that "inclusivity, not exclusivity" was the way forward, according to a transcript of his speech.

"Discrimination of any kind has no place in America’s armed forces," Carter said. "Young Americans today are more diverse, open and tolerant than past generations, and if we’re going to attract the best and brightest among them to contribute to our mission of national defense, we have to ourselves be more open, diverse and tolerant, too.  It’s the only way to compete in the 21st century."

The announcement followed a letter 23 senators sent to Carter in May calling for the policy to be updated to include gay, lesbian and bisexual service members. September will mark the four-year anniversary of the repeal of Don't Ask, Don't Tell, but the politicians wrote that the military was still not an equitable environment, BuzzFeed reported

"The absence of formal equal opportunity protections not only undermines foundational American principles of fairness and equality, it also presents an unneeded risk to national security by negatively impacting the morale and readiness of our all-volunteer force," wrote the group, which included Sens. Bernie Sanders, I-Vt., Elizabeth Warren, D-Mass., and Susan Collins, R-Maine.

Sexual orientation joins the list of qualities the Department of Defense cannot discriminate against, including race, color, religion, sex and national origin.

Carter did not explicitly address transgender people, who are still banned from serving in the military. But on Monday, the American Medical Association took up the topic itself. The organization approved a resolution saying there was "no medically valid reason to exclude transgender individuals from service," the Washington Post reported.

Read Carter's speech in full here.