Washington (CNN) A group of House Democrats from the Armed Services committee are demanding to know why the Pentagon didn't issue an official memo marking June as LGBT Pride Month.

Concerned that Pentagon leadership is "backing away from supporting and celebrating" its LGBT military members, Rep. Anthony Brown, D-Maryland, and seven of his Democratic colleagues penned a letter to Defense Secretary James Mattis asking him to explain the decision not to issue a memo.

The group of Democrats is also demanding answers as to why Defense Department leadership declined to address the Pentagon's annual Pride event.

"The absence of demonstrative support from DOD leadership at events like these can have the effect of isolating our LGBT service members and employees," the letter sent Thursday read.

CNN has reached out to the Department of Defense for comment.