US President Joe Biden has signed an order reversing a defence policy that largely barred transgender individuals from serving in the military.
It overturns the ban announced by Donald Trump in 2017, which Mr Biden has labelled "discriminatory".
The order immediately prohibits any service member from being forced out of the military on the basis of gender identity.
Mr Biden’s order says: "America is stronger, at home and around the world, when it is inclusive. The military is no exception.
"Allowing all qualified Americans to serve their country in uniform is better for the military and better for the country because an inclusive force is a more effective force. Simply put, it’s the right thing to do and is in our national interest."
The new order was signed by Mr Biden during a meeting with newly appointed Defense Secretary Lloyd Austin.
Mr Biden announced the move on Twitter, adding that "America is safer when everyone qualified to serve can do so openly and with pride".
The departments of Defense and Homeland Security have now been directed to take steps to implement the order for the military and the Coast Guard.
Both departments are also required to re-examine the records of service members who were discharged or denied re-enlistment due to gender identity issues under the previous policy.
They are to issue a progress report to the president within 60 days.
In June 2017, Mr Trump put forward a ban on transgender individuals serving "in any capacity" – tweeting that American defence could not afford to be "burdened with the tremendous medical costs and disruption" of their inclusion.
In the previous year, the Obama administration had enabled transgender individuals to serve openly and without discharge, setting out July 2017 as the starting point for transgender enlistment.
However, Mr Trump then delayed this enlistment date and called for additional study to determine if allowing transgender individuals to serve would affect military readiness or effectiveness, before sending his tweet in June.
A new policy approved in 2019 barred transgender troops and military recruits from transitioning to another sex and required most individuals to serve in their birth gender.
It meant current serving transgender troops and anyone who had enlisted before the effective date could continue with hormone treatments and gender transition if they had been diagnosed with gender dysphoria.
After that date, though, no one with gender dysphoria who was taking hormones or had transitioned to another gender was allowed to enlist.
Troops that were already serving and were diagnosed with gender dysphoria were required to serve in their birth gender and were barred from taking hormones or getting transition surgery.
In a statement made after Mr Biden’s order, Mr Austin said: "The Department will immediately take appropriate policy action to ensure individuals who identify as transgender are eligible to enter and serve in their self-identified gender.
"These changes will ensure no one will be separated or discharged, or denied reenlistment, solely on the basis of gender identity.
"Prospective recruits may serve in their self-identified gender when they have met the appropriate standards for accession into the military services."
Cover image: Joe Biden was sworn in as US President last week.