Ibrahim Hodeib, security chief in the Upper Egyptian city of Beni Suef, said that one protester was killed and 30 injured following an attack by unknown assailants, in a phone interview with private satellite channel CBC.

Journalist Shaimaa Mafhouz tells Ahram Online that a thousand-strong anti-Morsi rally in El-Modereya Square, the main square in Muslim Brotherhood stronghold Beni Suef, was fired at.

"A number of assailants, accused by protesters of being Islamist supporters of Morsi, attacked the rally...Some clusters of protesters scattered and hid inside the mosques surrounding the square; at the same time the armed forces mobilised to contain the situation. Assailants continued briefly to fire at the mosques where protesters were hiding but they ran away when the army arrived," Mahfouz said.

Millions of Egyptians are taking part in the widely-anticipated demonstrations calling for the resignation of President Mohamed Morsi, who hails from the Muslim Brotherhood, and snap presidential elections.

Deadly confrontations between the president's supporters and opponents have taken place intermittently since Wednesday in the run up to Sunday's protests, in which at least three were confirmed dead and hundreds injured.

The Beni Suef office of the Egyptian Popular Current, a leftist group led by opposition leader Hamdeen Sabbahi, claimed in a statement that 30 members of “the jihadist movement” in Beni Suef were the ones who fired at the protest and that several protesters were injured.

Mahfouz told Ahram Online she saw a child injured with a bullet to the shoulder.

Hodeib told Ahram Arabic news website that one suspect behind the violence is Al-Gamaa Al-Islamiya leader in the city, Ahmed Youssef.

Ahram Arabic reporter in Beni Suef Emad Abouzeid says the assailants fired birdshot at the protest, although others said that the assailants used live ammunition.

Tens of thousands of supporters of President Morsi remain in a sit-in in Cairo's Rabaa Al-Adawiya Square. Seventeen Islamist parties, led by the Muslim Brotherhood's Freedom and Justice Party, organised two mass rallies over the last week to defend Morsi's democratic legitimacy.