The American soldier sentenced to 35 years in jail for passing secret documents to WikiLeaks asked to be considered a woman on Thursday and requested sex change therapy.
"I am Chelsea Manning, I am a female," the private previously known as Bradley Manning said, in a statement passed to defense lawyers and read out on NBC television.
"As I transition into this next phase of my life, I want everyone to know the real me," the 25-year-old said, one day after being sentenced to decades of incarceration in military prison.
"Given the way I feel and have felt since childhood, I want to begin hormone therapy as soon as possible," the statement said.
"I also request that starting today you refer to me by my new name and use the feminine pronoun."
When asked if Manning would sue to force the government to provide hormone therapy and possibly gender reassignment surgery, defense lawyer David Coombs used the female pronoun when answering the question, a switch from his use of "he" when discussing Manning's trial.
"I don't know about the sex reassignment surgery... Chelsea hasn't indicated that that would be her desire, but as far as the hormone therapy, yes."
"I'm hoping Fort Leavenworth would do the right thing and provide that," he said.
A US military spokesman referred to Manning using the feminine pronoun, but said Fort Leavenworth military prison does not provide inmates with sex change treatment.
"We are aware that counsel representing the soldier convicted under the name Bradley Manning conveys that his client now openly identifies as female," Lieutenant Colonel Todd Breasseale told AFP.
"There is no mechanism in place for the US military to provide hormone therapy or gender-reassignment surgery for her."
Manning's sexuality and gender orientation were discussed at his trial.
The defense argued in mitigation that, as Bradley, he had been under severe psychological stress when he downloaded secret files and sent them to anti-secrecy activist Julian Assange's WikiLeaks website.
Under military law, Manning will be able to apply for parole in just over seven years, but will remain a soldier until a dishonorable discharge on release.
The former intelligence analyst spent most of his pre-trial detention at the Fort Leavenworth military base in Kansas and is expected to remain there.
Coombs said Manning had waited until after the court martial to make the bombshell announcement so as not to overshadow the case.
During the proceedings, the court heard that Manning struggled with homosexuality and gender issues while in Iraq and had complained of stress to a supervisor.
Coombs said Manning was not making the request in order to be transferred to a women's prison.
"No. I think the ultimate goal is to be comfortable in her skin and to be the person that she's never had the opportunity to be," he said.
"Inmates at the United States Disciplinary Barracks and Joint Regional Correctional Facility are treated equally regardless of race, rank, ethnicity or sexual orientation." said Pentagon spokesman Justin Platt.
"All inmates are considered soldiers and are treated as such with access to mental health professionals, including a psychiatrist, psychologist, social workers and behavioral science noncommissioned officers with experience in addressing the needs of military personnel in pre- and post-trial confinement."
While there is no precedent in military law for a soldier requesting a sex change while in custody, US federal judges have ruled in several cases that authorities must provide the treatment to civilian inmates.
Manning was arrested in 2010 while serving as a junior intelligence analyst at a US base near Baghdad after sending 700,000 documents -- military war logs and US diplomatic cables -- to WikiLeaks, which published them.
The young soldier has been hailed by supporters as a hero for exposing what they see as US abuses in the wars in Iraq and Afghanistan, but denounced by prosecutors as a traitor who put country and comrades at risk.