Australian whistleblower David McBride, who leaked classified documents revealing allegations of Australian war crimes in Afghanistan to the media, lost his appeal to reduce his prison term on Wednesday.

The Australian Capital Territory Court of Appeal rejected McBride's appeal to reduce the severity of a five-year and eight-month prison sentence imposed a year ago.

What did McBride's team say about the verdict?

McBride, who is a former military lawyer, said through his lawyers that Australians would be outraged by the Court of Appeal decision.

His lawyers said that they will challenge the decision in the High Court.

"We believe that only the High Court can properly grapple with the immense public interest and constitutional issues at the heart of this case," the lawyers' statement said.

"It cannot be a crime to expose a crime. It cannot be illegal to tell the truth," the statement added.

What was McBride's appeal?

Besides appealing for a reduction in his prison sentence, his appeal also focused on arguing that he leaked the documents in line with his duty to act in the public interest.

"It is my own conscience and the people of Australia that I answer to. I have kept my oath to the Australian people," McBride said in the lawyers' statement.

McBride wanted to argue that the duty came from the oath he swore to late Queen Elizabeth II when he joined the military.

Last year, McBride pleaded guilty to three charges, including theft and handing out documents classified as secret to the media.

He has been in Canberra's prison since October last year. His appeal was heard in March.

Rights groups find court's decision unfair

Rights advocates have criticized the prosecution, saying that McBride remains the only person to be imprisoned over allegations of war crimes committed by elite Australian special forces troops in Afghanistan between 2005 and 2016.

The Human Rights Law Centre (HRLC) expressed its surprise over court's dismissal of McBride's appeal to reduce his sentence.

"That's a very long sentence, particularly compared to comparable cases, so I was surprised as to the court's failure to accept the sentencing appeal," HRLC associate legal director Kieran Pender was cited by Australia's ABC public broadcaster as saying.

"I think that only underscores the ongoing travesty that is his prosecution," he declared.

Edited by: Saim Dušan Inayatullah