|Protesters are still camped out in Cairo's Tahrir Square, calling for faster change [Reuters]
Egyptian military police fired shots in the air and beat demonstrators blocking a main road in the Mediterranean city of Alexandria, witnesses said, in a move that could further sour relations between the army and civilians.
Friday's events were a rare display of violence in two weeks of largely peaceful protests in Alexandria, Cairo and Suez following a court decision to free on bail 10 policemen accused of killing protesters during the uprising that overthrew President Hosni Mubarak in February.
Witnesses told the Reuters news agency that the clash in Alexandria erupted after hundreds of protesters blocking the coastal road near the army's northern command headquarters refused to leave the area.
Police fired shots in the air and charged demonstrators who responded by hurling stones at them.
"The military police are firing in the air. They are also beating protesters with batons and kicking them hard," a witness said.
In Suez, the state MENA news agency said military police "foiled" an attack on the local security headquarters and detained four people after a crowd attacked the building with a firebomb and stones.
The violence in Alexandria and the incident in Suez angered hundreds of protesters camping in Cairo's Tahrir Square, witnesses said.
A crowd of thousands began marching towards the headquarters of the ruling military council, chanting: "Down with the Field Marshal"- a reference to the council head, Field Marshal Mohammed Hussein Tantawi.
Witnesses said military police fired in the air to stop them approaching the building.
The standoff continued into the early hours of Saturday, also blocking traffic at a busy square across the city from Tahrir square.
Many protesters have grown mistrustful of the military, accusing it of dragging its feet in bringing former regime officials to trial.
More than five months after mass street demonstrations drove Mubarak from power, many Egyptians worry that their "revolution" has stalled.
Hassan al-Ruwaini, a member of the ruling military council, told state television the council was trying to meet
protesters' demands, but it was up to the courts to free or convict suspects on trial.
The ruling military council, in a statement on its Facebook page, denied the authorities used force against demonstrators anywhere in Egypt and accused the April 6 Movement - one of the groups behind the uprising -of trying to drive a wedge between the armed forces and the people.
Egypt's interim rulers have reshuffled Prime Minister Essam Sharaf's cabinet and promised to speed up trials and political reforms, but thousands kept up protests across Egypt on Friday to back demands for the policemen's trials to be held soon.
Sharaf, in a speech after his new cabinet was sworn in on Thursday, promised to set up an anti-corruption body and work to scrap a 30-year-old emergency law. He also said the interior minister would appoint a human rights adviser, and human rights and civil society groups would have access to prisons.
But activists said this was not enough.