The Anti-Coup Pro-Democracy Alliance, which is one of the largest political formations in Egypt, organized Saturday’s sit-in protest outside Rabia al-Adawiya Mosque in eastern Cairo.
The protesters chanted slogans against army chief General Abdel Fattah al-Sisi.
The demonstrators said they would maintain open-ended sit-in protests until Morsi is reinstated.
They have promised to remain steadfast despite threats by the interim government to use force to clear the area.
Egypt has witnessed non-stop demonstrations in support of the country’s first democratically elected president, since he was toppled by the army more than a month ago.
On Wednesday, Egypt’s interim Prime Minister Hazem al-Beblawi called on supporters of Morsi to immediately leave their protest camps in Cairo.
“We ask them now again, once again, to quickly leave to their homes and their jobs. The government’s patience to bear this is nearly expired,” Beblawi said in a televised speech.
“The cabinet affirms that the decision to disperse the Rabaa al-Adawiya and al-Nahda sit-ins is a final decision, on which all agree, and there is no going back on it,” he added.
Beblawi also accused the protesters of inciting violence and said their sit-ins are not peaceful.
On July 3, the army chief announced that Morsi, a leading former member of the Muslim Brotherhood, was no longer in office and declared that the head of the Supreme Constitutional Court, Adly Mahmoud Mansour, had been appointed as the new interim president of Egypt. The army also suspended the constitution.
Army officials said Morsi, who took office in June 2012, was being held “preventively” by the military.
On July 5, Muslim Brotherhood supreme leader Mohammed Badie said the coup against Morsi was illegal and millions would remain on the street until he is reinstated as president.
Badie vowed to “complete the revolution” that toppled the Western-backed regime of former Egyptian dictator Hosni Mubarak in 2011.
The Egyptians launched a revolution against the pro-Israeli regime on January 25, 2011, which eventually brought an end to the 30-year dictatorship of Mubarak on February 11, 2011.