The founder of WikiLeaks, Julian Assange, says a US whistleblower convicted of espionage and theft for leaking secret documents is a "hero".

Soldier Bradley Manning will be sentenced later today after he was last night found guilty of 20 charges.

He faces up to 136 years in prison. 

In a video message released overnight, Julian Assange, whose website published details of thousands of US government cables said Manning's conviction should be reversed. 

 

Manning not guilty of 'aiding the enemy'

Despite his conviction, Manning was cleared of the most serious charge: "aiding the enemy". It carried a sentence of life without parole.

Many of Manning's critics within US Congress say he is a traitor who put the lives of his fellow servicemen and women at risk. 

However, his supporters say he should be praised for exposing and opening a debate about US foreign policy.

Journalist and author John Pilger says US President Barack Obama is keen to clamp down on whistleblowers.