ADDIS ABABA (AFP) - Ethiopia's government on Monday named the co-pilot of an Ethiopian Airlines flight who hijacked his aircraft, describing him as "medically sane" and saying the incident "beggars belief".

Information Minister Redwan Hussein named the hijacker as 31-year-old Hailemedehin Abera Tagegn, and said he had been working with the national carrier for five years and had no criminal record.

"So far it is known that he was medically sane, until otherwise is proven through the investigation which is going on right now," the minister told reporters.

"So the intention, what forced him to hijack his own plane, still beggars belief...any political, social or economic reason would not make sense to hijack your plane and be a criminal," he said.

"We don't see any criminal record... and there was no reason for him to be prosecuted so there was no reason for him to flee," he added.

The minister said the passengers included 139 Italians, 11 Americans, 10 Ethiopians as well as nationals from Nigeria, Romania, France, Ireland, Germany and other countries.