A former Libyan premier and oil minister, whose body was found in the Danube river close to where he had a residence in Vienna, drowned, according to autopsy results.

Austrian police spokesman Roman Hahslinger also said the autopsy results on Shukri Ghanem's body show there were no signs of violence.

Mr Hahslinger suggested the death may have been an accident and said Mr Ghanem had complained to his daughter late on Saturday that he was not feeling well. He said no suicide note had been found, and there was no evidence Mr Ghanem was under threat.

The results of toxicological tests are expected later this week, as part of the investigation into the drowning.

Mr Ghanem abandoned Colonel Gaddafi's regime to support the rebels.

He served as his country's oil minister until last year. He left Libya for Tunisia and then Europe in June, as insurgents were pushing to topple Gaddafi, and subsequently announced support for the rebels.

He was said to be autocratic at home but reporters covering the Organisation of the Petroleum Exporting Countries remembered him as a friendly man who gracefully took even late-evening calls.

With advanced degrees in law and economics, Mr Ghanem served in senior positions within Vienna-based Opec before his appointment as Libyan prime minister in June 2003, an office he held until 2006.

Considered a member of Gaddafi's inner circle until his defection, he insisted Libya bore no responsibility for the Lockerbie plane crash.

He also repudiated Libyan responsibility in the 1984 shooting death of WPC Yvonne Fletcher.

Such comments branded him as a loyal servant of the Gaddafi clan. At the same time, he worked quietly from the inside to change the face of Libya.

Mr Ghanem's efforts were supported by Saif al Islam, the Gaddafi son associated with the reform wing.