Image caption Former Defence Secretary Donald Rumsfeld has been represented by the justice department

A US judge has ruled that a former American military contractor who claims he was tortured in Iraq can sue former Defence Secretary Donald Rumsfeld.

The man's lawyers say he was abducted by the US military and abused at a US military detention centre near Baghdad.

The government says he was suspected of helping pass information to the enemy, although he was never charged.

It is the second time that a federal judge has allowed a US citizen to sue Mr Rumsfeld over torture claims.

The man who brought the suit approved by US District Judge James Gwin is an army veteran in his 50s.

He was released from Camp Cropper detention centre in Iraq in 2006.

In 2008, he filed a suit at the US District Court in Washington claiming that Mr Rumsfeld had personally approved interrogation techniques involving torture on a case-by-case basis, the Associated Press news agency reports.

Mike Kanovitz, a lawyer for the former contractor, said it appeared his client had been held to prevent him speaking about a contact he had made with a sheikh while gathering intelligence in Iraq.

Mr Rumsfeld has been represented by the Obama administration, through the justice department.

It argues that Mr Rumsfeld cannot be sued personally for official conduct, that wartime decisions are the constitutional responsibility of Congress and the president and cannot be reviewed by a judge, and that the case risks creating a threat of liability that could hamper future military decisions.

Mr Rumsfeld is appealing against a 2010 ruling by an Illinois judge who said two other former contractors held at Camp Cropper could pursue claims that they were tortured using methods approved by the former defence secretary.