The Lawyer of Chelsea Manning, a former US soldier who is currently serving a prison sentence for disclosing secret diplomatic and military documents to WikiLeaks in 2010, has put forth a petition requesting President Barack Obama to grant clemency and reduce the rest of her 35-year sentence to the more than six years she has already served.

Manning's punishment is the longest period of incarceration awarded to any leaker in American history.

In the copy of her petition, released to the New York Times, her lawyer pointed out that she never made excuses and accepted responsibility for her actions but due to the attention the case had drawn, the Army wanted to make an example out of her by giving such a long sentence.

"In a case like Ms Manning's... the military judge has no way of knowing what constitutes fair and reasonable punishment," the law firm wrote in its letter to the office of the Pardon Attorney.

In a statement alongside the petition, she acknowledged that what she had done was wrong. "I am not asking for a pardon of my conviction.

Who is Chelsea Manning?

Chelsea Manning is a transgender Army private, who was born male and was formerly known as Pfc. Bradley Manning.

She was incarcerated under the Espionage Act after pleading guilty to providing WikiLeaks with more than 700,000 documents, videos, diplomatic cables and battlefield accounts.

She is currently being held at the Fort Leavenworth military prison in Kansas where she has attempted to commit suicide twice.

"The sole relief I am asking for is to be released from military prison after serving six years of confinement as a person who did not intend to harm the interests of the United States or harm any service members," she explained.

Her statement was accompanied by letters from Daniel Ellsberg, who was responsible for leaking a classified history of the Vietnam War known as the Pentagon Papers; Morris Davis, a former military commissions chief prosecutor; and legal commentator and journalist Glenn Greenwald.

"I believe now, in the six and a half weeks we have remaining, we all have to ask President Obama to do with his powers good things before he leaves, before a new president comes in, and I really believe that he should commute Chelsea Manning's sentence to time served," Ellsberg said.