At least 22 people were shot and killed on Wednesday as Ethiopian security forces clashed with stone-throwing protesters accusing the ruling party of fraud in last month's elections.

Hospitals in the capital, Addis Ababa, were filled with people injured in the demonstrations, while crowds of relatives wept outside.

Police opened fire on Wednesday to disperse protesters in the Mercato, a vast open-air marketplace in the capital, and in the Piazza, a busy central area of shops and bars.

A reporter for the Associated Press news agency saw 11 bodies in a room in the capital's Black Lion hospital, at least four with gunshot wounds to the head.

"The police were running at the crowd, firing shots. I got shot in my leg," Getu (22) told AP. "I was just trying to get home to avoid the trouble."

Taxi drivers and shop owners in the capital went on strike on Wednesday, joining a protest that had been started by students on Monday.

Hundreds of students have been arrested for defying a ban on public protest which was imposed by Meles Zenawi, the Prime Minister, after the elections on May 15. Although diplomats initially declared the elections to be the fairest the country had ever experienced, EU observers voiced doubts over irregular vote counting and biased reporting by the state-controlled media.

Opposition parties have alleged that gunmen intimidated voters, that ballot boxes were stuffed or had disappeared, and that the number of ballots in some constituencies exceeded the number of registered voters.

The final results have not yet been announced, three weeks after the polls, but according to provisional results the opposition won a landslide in the capital.

The government said it regretted the loss of life but blamed it on the opposition, which was described in an official statement as "destructive forces who wish to plunge our country into terminal crisis".

The statement read: "The opposition political parties, especially the leadership of the Coalition for Unity and Democracy, are playing the leading role in instigating violence."

According to the government, seven buses were destroyed during the violence, and vehicles, businesses and banks were attacked. On Tuesday, students had thrown stones at the police, who responded by storming a technical college and arresting about 100 people.

The students were beaten with batons and rifle butts by the police, who also fired shots in the air, witnesses said.

On Monday, about 500 people were arrested and a girl died in clashes which began when students defied the government's 30-day ban on demonstrations.

Two foreign radio stations, Voice of America and Deutsche Welle, ceased broadcasting in Ethiopia on Wednesday after the government revoked their permits.

Foreign press photographers covering the protests said that police had confiscated memory cards from their cameras.

One man injured in the demonstrations, who refused to give his name because of fear of retribution, said that the army had fired on fleeing people. He said that he had been caught up in the street protests rather than taking part in them.

Atenyesh Mamo (39) a mother of two, said she had been shot in the waist after opening the door to her home to bring in her seven-year-old son as the protests escalated. "I don't know why they shot me as all I was doing was looking for my son," she said while waiting for an x-ray. "I am very angry and I don't know why the soldiers want to shoot us."

Dozens of people were wounded in Wednesday's violence, suffering gunshots to the chest, legs, arms or back. Most of the victims were young men. Nearly an hour after the shooting, ambulances and private vehicles continued to bring the wounded to the city's main hospital. Several hundred people gathered there, some wailing or shouting. Doctors said they were treating more than 100 people, many with serious injuries.

The main political opposition, the Coalition for Unity and Democracy, said that it was not behind the strike. "Our sense is that the government is deliberately targeting us and fomenting violence to stop the electoral process and then blaming it on the opposition," said the vice-chairperson, Berhanu Nega.

"We have been saying all along that the public must be calm and patient and wait for the outcome of the investigations into the election."

According to the provisional voting results, the ruling party, Zenawi's Ethiopian People's Revolutionary Democratic Front, and its allies have won 320 seats so far, giving it a majority in the 547-member Parliament. The opposition parties have won almost 200 seats, a major gain compared with the 12 they had in the previous parliament.

Ethiopia is one of the world's poorest countries and has endured centuries of autocratic rule, first under emperors, including Haile Selassie, and then under a Marxist government. Zenawi, a member of Tony Blair's Africa commission, has pledged to introduce greater democracy.