Doctors at three hospitals in central Addis Ababa said 22 people had either been brought to their facilities dead or died shortly after arriving following clashes in the downtown area between security forces and protestors.

Eleven of the dead were at the Black Lion hospital where at least 100 injured people, many with gunshot wounds, crowded the emergency room, according to an AFP correspondent who saw the bodies.

The AFP correspondent said there were more than 40 injured people, most with gunshot wounds, at Saint Paulus.

The dead and injured were caught in clashes between police and protestors in three downtown districts, particularly in the Mercato area where diplomatic sources said a bus had been set on fire.

Three people being treated for gunshot injuries sustained in the Mercato area at the Black Lion hospital denied having been involved in any demonstration.

"I was looking for my son, I opened the door and I was shot," said 39-year-old Ateneyesh Mamo, a mother of two with a wound to the pelvis.

"I'm very angry because I wasn't protesting, I wasn't doing anything, I was just looking for my seven-year-old son," she said. "I don't understand what happened."

The city administration said it had ordered security forces to deal severely with a rash of "hooliganism" linked to the demonstrations, including the blocking of roads, housebreaking and "gatherings and protests."

The government defended the actions of security forces which they said were necessary to prevent hooligans from looting and destroying property and blamed the opposition for the violence.

Information Minister Berekat Simon said the government regretted any deaths but insisted the crackdown had been necessary to protect the population of Addis Ababa from opposition-inspired looting and crime.

He placed blame for the violence squarely on the opposition Coalition for Unity and Democracuy (CUD), which has been complaining of massive ruling party fraud in last month's disputed elections.