In a letter to Secretary of State Mike Pompeo, 17 Senate Democrats are demanding answers about the department's decision to ban the flying of rainbow flags at U.S. embassies and diplomatic missions.

(Related: Despite rejected requests from Trump admin, some U.S. embassies fly rainbow flag.)

The rainbow flag is a symbol of the LGBT social movement and is widely displayed during Pride month.

In the letter, dated June 13, the Senate Democrats, led by Massachusetts Senator Edward Markey, assert that the ban is “sending a powerfully negative message to the rest of the world about the U.S. commitment to LGBTI human rights.”

While Pompeo last year issued a Pride proclamation, none was forthcoming this year.

“This community requires our moral leadership and support,” the letter states. “But preventing the official flying of rainbow flags and limiting public messages celebrating Pride Month signals to the international community that the United States is abandoning the advancement of LGBTI rights as a foreign policy priority.”

(Related: Mike Pence calls ban on rainbow flags at U.S. embassies “right decision.”)

The group of senators called on Pompeo to provide answers on the ban and why it was implemented.

Senators who signed the letter include Markey, Kirsten Gillibrand (D-N.Y.), Tammy Baldwin (D-Wisc.), Elizabeth Warren (D-Mass.), Sherrod Brown (D-Ohio), Kamala Harris (D-Calif.), Bernie Sanders (I-Vt.), Bob Casey (D-Penn.), Jacky Rosen (D-Nev.), Tina Smith (D-Minn.), Jeanne Shaheen (D-N.H.), Cory Booker (D-N.J.), Jeff Merkley (D-Ore.), Amy Klobuchar (D-Minn.), Maggie Hassan (D-N.H.), Tim Kaine (D-Va.), Richard Blumenthal (D-Conn.) and Patty Murray (D-Wash.).

A companion letter signed by 50 House Democrats also calls on the State Department to reverse course and lift the ban on rainbow flags at U.S. Embassies.