Image caption As vice-chairman of the Joint Chiefs of Staff, General Cartwright was part of President Obama's inner circle of security advisers

A retired high-ranking US general is under investigation for allegedly leaking classified information about a covert cyber attack on Iran's nuclear programme, US media report.

Retired Marine General James "Hoss" Cartwright has been informed by the Justice Department that he is a target in their inquiry, NBC News reports.

Gen Cartwright was vice-chairman of the Joint Chiefs of Staff from 2007-11.

The Stuxnet virus temporarily disabled Iranian nuclear facilities in 2010.

The New York Times gave a detailed account last year about the virus, and how it temporarily took out nearly 1,000 centrifuges that Iran was using to purify uranium.

The newspaper said the attack was part of a wider cyber operation called Olympic Games, that began under President George W Bush and accelerated under President Barack Obama.

The revelations prompted the US attorney to order an investigation into the leaks.

NBC News quoted legal sources as saying that 63-year-old Gen Cartwright had a received a letter from the Justice Department informing him that he is a target in their investigation.

A target is a suspect in a criminal case who has not yet been formally charged but is expected to be, the Washington Post reports.

Gen Cartwright was part of President Obama's inner circle of security advisers before he retired in 2011.

Both his lawyer and justice department officials have refused to comment on the reports.