Bradley Manning, the US soldier who leaked secret US government documents to the Wikileaks website, has announced he wants to live as a woman.

"As I transition into this next phase of my life, I want everyone to know the real me," Manning said a the statement.

"I am Chelsea Manning. I am a female. Given the way that I feel, and have felt since childhood, I want to begin hormone therapy as soon as possible. I hope that you will support me in this transition."

"I also request that, starting today, you refer to me by my new name and use the feminine pronoun (except in official mail to the confinement facility)," Manning's statement read.

"I look forward to receiving letters from supporters and having the opportunity to write back."

But Fort Leavenworth military prison in Kansas, where Manning is due to serve out her sentence, said on Thursday that it would not provide trans treatment beyond psychiatric support, in a move criticized as unconstitutional by activists and LGBT groups, according to The Guardian.

A US military judge sentenced Manning to 35 years in prison Wednesday for leaking classified documents to the anti-secrecy group WikiLeaks.

Manning had already admitted passing hundreds of thousands of battlefield reports and diplomatic cables to Wikileaks while stationed in Iraq in 2010, saying in a pre-trial hearing he had leaked the secret files in order to spark a public debate about US foreign policy and the military.