The WikiLeaks website has begun releasing dozens of classified US files which cover the procedures for detainees in military custody.

The internal documents cover detainee policies in Iraq and Guantanamo Bay, as well as interrogation manuals and prisoner treatment.

WikiLeaks said while the files show that violence against detainees was prohibited, military officials were allowed to destroy recordings of interrogations.

The files also appear to discuss how to "disappear" detainees into the custody of other US agencies while keeping their names off the books.

The whistle-blowing website's motto is "to publish fact-based stories without fear or favour".

WikiLeaks has angered officials in the United States in recent years after the release of thousands of classified documents.

US soldier Bradley Manning is accused of passing on the secret files, which relate to the conflicts in Iraq and Afghanistan, Guantanamo Bay detainee assessments and US state department diplomatic cables.

The private faces a total of 22 charges and, if convicted, he could be sentenced to life in jail. His trial is due to start in February.

The latest WikiLeaks release comes as Ecuador voiced concern about the health of the website's founder Julian Assange.

The Australian has been holed up inside Ecuador's embassy in London since June to avoid extradition to Sweden, where he is wanted for questioning over sexual assault allegations.

Ecuador has reportedly asked Britain to guarantee him safe passage to a hospital if he requires treatment.