At least six protesters have been killed as Muslim Brotherhood supporters clashed with police in Cairo and other Egyptian cities, medical and security sources said.

Three people were killed in protests in Cairo on Friday. One protester was shot dead by police in Ismailia governate after joining a march following midday prayers, while another protester died after being shot in the head in the rural province of Fayoum, southwest of Cairo.

A demonstrator was killed in Alexandria, officials said. A total of 42 people had been injured during Friday protests, the health ministry added. Meanwhile, at least 122 people have been arrested around the country, according to officials.

Protesters set fire to a police vehicle in Cairo using petrol bombs as police fought street battles with rock-throwing protesters in the capital, an AFP reporter said.

"We are not afraid, we love Egypt and what we are doing is for Egypt," said Mohamed Dahi, a 39-year-old protester, as he distributed leaflets calling for the boycott on a referendum on a new constitution to be held later this month.

"I am against all injustice and the military rule. I won't accept any military rule in Egypt," Dahi told AFP as as he participated in a protest along with his 10-year-old son.

Chants against army

Demonstrators chanted "Down with military rule" and slogans against army chief Abdel Fattah al-Sissi, who removed Mohammed Morsi from the presidency in July.

Cairo's main squares were sealed off by security forces using barbed wire and military vehicles. They included Tahrir Square, as well as Rabaa al-Adawiya and Nahda squares, which were the sites of a bloody crackdown on Morsi's supporters in August.

The clashes took place less than two weeks before a vote on a new constitution, a milestone in the road map which the army-backed authorities say will pave the way for a return to a democratic rule by next summer.

Protesters opposed to the army's overthrow of Morsi have been holding daily demonstration in Cairo and in other cities ever since the military government declared the Muslim Brotherhood a "terrorist" group last month, a move that upped the penalties for dissent.

Reuters And AFP