Under the policy, transgender people who join the military after the order takes effect will have to serve in the gender they were assigned at birth. Service secretaries will be allowed to grant waivers on a case-by-case basis, according to the Hill magazine.
According to the memo signed on Tuesday by acting Deputy Defence Secretary David Norquist, the policy will go into effect in 30 days.
The directive was being issued after a court last week lifted the last of the orders preventing the transgender military policy from taking effect.
The Trump administration said it planned to move forward with the policy following the judge's ruling last week.
Still, advocates for transgender troops argued that the Pentagon was constrained by a fourth injunction, pointing to a stipulation in the order that allows for a period of time for the plaintiff to decide whether they want a rehearing in front of the court's full bench, the report said.
"With brazen disregard for the judicial process, the Pentagon is prematurely and illegally rolling out a plan to implement the ban when a court injunction remains in place prohibiting them from doing so," said Jennifer Levi, the Director of the Transgender Rights Project of GLBTQ Legal Advocates & Defenders (GLAD).
GLAD is serving as co-counsel in the lawsuit at issue.
"In addition to being unlawful, moving forward with this ban is also deeply immoral and deeply insulting to the many transgender troops who are bravely serving their country," Levi added.
Transgender troops have been serving openly since June 2016 when the (Barack) Obama administration lifted the previous ban on their service.
In July 2017, Trump tweeted he would reverse that policy, saying he would "not accept or allow Transgender individuals to serve in any capacity in the US military".
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)