Six people have been killed in Cairo in the latest clashes between opponents and Islamist supporters of Egypt's deposed President Mohamed Mursi.

The violence broke out before dawn yesterday near a Muslim Brotherhood protest at Cairo University.

Mursi supporters have camped out there since the Army removed the Islamist politician from power after protests against his rule.

The Brotherhood described it as an attack on peaceful protesters. Police sources said hundreds of Mursi supporters clashed with residents, street vendors and others near the sit-in. They said gunshots were fired and stones were thrown.

With the Brotherhood vowing to stay in the streets, the bloodshed was a fresh example of the ­instability facing Egypt as the interim Government moves along an army-backed roadmap towards elections in about six months.

A health ministry official was quoted as saying six people had been killed and 33 were wounded, bringing to nine the number of deaths in two days.

At least 15 burned-out cars lay abandoned around the Cairo University area where the clashes took place.

Brotherhood members with sticks guarded the entrance to the protest site after the clashes calmed, while residents stopped cars on the road to Cairo University to check for weapons.

About 100 people have died in violence since the army deposed Mr Mursi and replaced him with an interim administration led by the Adli Mansour, the head of the constitutional court. The Brotherhood said on its website that seven "martyrs" had been killed overnight in two separate attacks on Mursi supporters, one at Cairo University and another during a march near a bigger round-the-clock sit-in in the north of the city.

The Brotherhood says it will maintain the sit-in until Mr Mursi, held by the army in an unknown location since his overthrow after a year in power as Egypt's first freely elected president, is reinstated.

In a statement, the ­Brotherhood's Freedom and Justice Party said: "Leaders of the military coup continue to terrorise the peaceful protesters in Egypt."

Mr Mursi's family said on Monday it would sue the army for holding him without charge. The United States, which gives Egypt $1.3 billion (£860m) a year in ­military aid, has called for Mr Mursi's release and an end to "all politicised arrests and detentions".

Some residents near the Islamist movement's main protest area in Nasr City have filed a complaint with the public prosecutor asking for the protesters' removal.

A security source said a court was expected to rule soon "to give the army a legal basis to end the protests".

The National Salvation Front, an alliance of liberal and leftist parties that supported Mursi's ousting, condemned what it called attacks by Brotherhood supporters on protesters in the last three weeks.

Earlier, in separate clashes, a civilian and policeman were killed in the North Sinai region, near Egypt's borders with Israel and the Palestinian Gaza strip, where hardline Islamists have stepped up attacks on security forces.

A security vacuum following the 2011 uprising that ousted President Hosni Mubarak resulted in a surge of attacks in North Sinai.

At least 20 have been killed in violence there since Mr Mursi's overthrow.