On November 20, police and troops made a violent attempt to evict the demonstrators, firing tear gas and beating them with truncheons.

However, the protesters returned less than an hour later, chanting slogans against Egypt's military rulers.

The European Union said it condemned the violence "in the strongest terms".

There were also clashes in other cities including Alexandria, Suez and Aswan.

A total of 11 people were reportedly killed on November 20 and two on November 19, according to medical sources. Health officials say as many as 900 have been injured, including at least 40 security personnel.

The demonstrators, some wearing gas masks, say they fear Egypt's interim military rulers are trying to retain their grip on power.

The violence comes a week before the country's first parliamentary elections since President Hosni Mubarak was overthrown in February.