The lawyers of jailed US army whistleblower Chelsea Manning have confirmed that she attempted suicide in prison last week.

Manning, the 28-year-old soldier is serving a 35-year sentence after she was convicted in 2013 of leaking more than 700,000 secret military and US State Department documents to anti-secrecy website Wikileaks.

The soldier's legal team released a statement on Monday detailing that Manning's "attempt to take her own life was unsuccessful". 

"She wants everyone to know that she remains under close observation by the prison and expects to remain on this status for the next several weeks," the statement said.

Manning's lawyers also accused the US military of violating her privacy for publicly revealing that she had been hospitalised.  

"The government's gross breach of confidentiality in disclosing her personal health information to the media has created the very real concern that they may continue their unauthorized release of information about her publicly without warning," the statement said.

Manning was an intelligence analyst in Iraq at the time that the documents were sent to WikiLeaks.  

A tweet posted on Monday on her behalf read:

I am okay. I'm glad to be alive. Thank you all for your love <3 I will get through this. #standwithchelsea

"For us, hearing Chelsea's voice after learning that she had attempted to take her life last week was incredibly emotional," her lawyers said.

"She is someone who has fought so hard for so many issues we care about and we are honoured to fight for her freedom and medical care."

Initially arrested as Bradley Manning, the soldier later announced she would start living as a female and filed a transgender prisoner rights lawsuit.

She appealed her conviction, arguing that her sentence was "grossly unfair" and that her actions were those of a naive, troubled soldier who aimed to reveal the toll of the wars in Iraq and Afghanistan.

The appeal contends Manning's disclosures harmed no one, but prosecutors said the leaked material damaged US security and identified informants who helped US forces.