Rival rallies held in Cairo

At least three people have died after clashes between loyalists and opponents of ousted Egyptian president Mohamed Morsi, as tens of thousands of people have demonstrated in cities across Egypt.

The three people were killed during clashes between rival demonstrators in the Nile Delta town of Mansoura. At least six others were injured in those clashes.

The country's military, meanwhile, has warned that it may crack down violently on any future mass protests against the overthrow of the president that it carried out on July 3. 

A vast pro-Morsi crowd gathered at Cairo's Rabaa al-Adawiya mosque on Friday, where the former president's supporters have camped out since the military overthrew him.

About 10,000 protesters then set off in the direction of an elite military compound, scene of the deadliest violence since Morsi's overthrow, carrying pictures of the deposed president and chanting slogans.

They were blocked by soldiers and armoured vehicles.

"Islamic, Islamic," they shouted, of their hopes for an Islamic state, as formations of fighter jets flew overhead and military helicopters whirled in the sky.

Late on Friday afternoonm Egypt's armed forces fired teargas at some of the pro-Morsi protestors who were heading towards the presidential palace on a road previously sealed off by the army. Following the teargas the crowd stopped moving forward, but have maintained their position.

Smaller rallies also took off elsewhere in Cairo, in Egypt's second city of Alexandria, and other parts of Egypt after Morsi's Muslim Brotherhood had called for a day of protests dubbed "Breaking the Coup".

Thousands of supporters of the military coup, meanwhile, gathered at a rival rally in Cairo's Tahrir Square.

They set off firecrakers and chanted "The army and the people are one!"

Their demonstrations have been far smaller since the mass rallies clamouring for Morsi's resignation in the days leading to the coup.