Widespread violence is sweeping through Egypt threatening to deepen the crisis in the country as supporters of ousted president Mohamed Morsi remain defiant.

More than 26 people have been killed across Egypt. Since the recent wave of protests began, at least 50 people have been killed. The Muslim Brotherhood said the dead include 17 of its members.

At least a dozen people have been killed in the Mediterranean city of Alexandria and more than 200 injured. Many of them are thought to have been shot dead.

The protests turned violent shortly after Morsi's supporters were reported to have been killed on the outskirts of Cairo.

Large groups of Morsi's supporters crossed the bridge over the Nile in the capital taking on the Islamist president's opponents near Tahrir Square.

Witnesses said gunshots were heard in the area. Pro-and anti-Morsi protesters also pelted stones at each other, injuring many.

For a brief while, the Egyptian army managed to bring down the violence in Cairo, but nationwide protests continue to snowball. Security forces fired teargas to control the situation, but without much effect.

While the Friday of Rage protests saw scores rallying against Morsi's ouster, the rebel campaign is also pressing ahead with its demonstrations and Sunday is expected to witness "the greatest rally" nationwide.

"The Egyptian people will not hesitate to protect their revolutionary legitimacy that has reflected the people's will against the tyrants who do not want stability in Egypt," the opposition, which launched the recent anti-Morsi movement, said in a statement.

The rebel campaign decried attempts to "smear our glorious revolution", and "portray the people's will" as a military coup.

Their statement warned against any foreign intervention in Egypt's internal matters.

Meanwhile, the military is continuing its crackdown on the Brotherhood, arresting more leaders and members of the group.

They include the deputy leader of the Brotherhood, Khairat el-Shater, on suspicion of inciting violence.

The army, which installed a top judge of the Egyptian constitutional court as interim leader, is likely to name a new prime minister later in the day.

The US has condemned the latest violence and urged the leaders to resolve the crisis.

UN chief Ban Ki-moon has also expressed alarm over the situation.