House Democrats plan to call on a key immigration agency to release all transgender people who are currently being detained, arguing that the U.S. has failed to follow guidelines to protect individuals who face more perilous conditions in detention than other migrants.

"We write to demand the release of all transgender people currently detained by Immigration and Customs Enforcement (ICE)," the letter to ICE is expected to say, according to an early copy obtained by The Hill.

"Transgender migrants and asylum seekers are particularly vulnerable to sexual harassment, solitary confinement, physical assault, and medical neglect. These inhumane conditions and systematic abuses are evidenced in countless reports and accounts by formally detained people," continues the letter, which will be addressed to acting Homeland Security Secretary Chad Wolf and acting ICE Director Matthew Albence.

The letter cites research articles from the Human Rights Campaign, Amnesty International and the Center for American Progress in arguing that due to their gender identity, transgender migrants are more likely to face "the pervasive use of solitary confinement" and that they are "97 times more likely to be sexually victimized" compared to "their cis-gender and straight counterparts in detention."

Rep. Mike Quigley (D-Ill.), who is leading the effort, circulated a letter to other Democratic colleagues last week seeking their signatures on his ICE letter, in which he argues there is a legal basis for releasing the transgender detainees.

The letter will make the case that ICE has yet to comply with the fiscal 2020 spending report, which includes language that dictates how the agency should handle the detention of transgender people.

He argues that since they have not followed such guidelines, ICE is "legally obligated to immediately release all transgender individuals currently in its custody."

Democrats will argue that ICE has failed to comply with a 2015 ICE memo titled "Further Guidance Regarding the Care of Transgender Detainees," in which the agency's Enforcement and Removal Operations is directed to consider "initial placements for transgender people."

Such places, according to the memo, include facilities that have incorporated modifications designed to improve transgender care, designated facilities with protective custody units for transgender detainees and facilities that have demonstrated "best practices in the care of Lesbian, Gay, Bi-sexual, Transgender, or Intersex detainees" as it relates to medical care and personnel with sensitivity and awareness training. Transgender people can also make transfer requests as it relates to his or her transgender identifications.

Under the fiscal 2020 Department of Homeland Security appropriations bill, ICE is directed "to limit the detention of individuals who self-identify as transgender to facilities," which points back to the 2015 memo. The exception, according to the text, is if "the individual has voluntarily declined placement in such a facility after being informed of the opportunity to do so."

Quigley says ICE has not provided such modifications as the 2015 memo lays out, arguing that the agency is "legally obligated" to release such individuals.

"As far as we are aware, no facility has ever entered into a contract modification pursuant to the 2015 memo, which means that by the plain text of this language ICE is now legally obligated to immediately release every transgender person in detention," Quigley wrote to colleagues.

"The agency has options in how it achieves this - it can release people to the community or into supervised alternative-to-detention programming, but it must release them," he added.

Quigley's office, which did not immediately respond to comment, set Friday as the deadline for signing onto the letter.

"The United States is bound by domestic and international law to protect-not punish-vulnerable populations escaping from persecution. We demand that ICE abide by these laws by immediately granting the release of all people who identify as transgender currently in their custody," the letter concludes.