Egypt's interim president is urging people to remain calm and abstain from violence following a new round of deadly clashes in Cairo.
Interim President Adly Mansour spoke on state television late Monday, telling Egyptians that reconciliation is necessary for the country to move forward.
His comments came after new clashes erupted in Cairo between supporters and opponents of ousted President Mohamed Morsi.
Security officials said Monday's fighting started with stone-throwing when a group of Morsi supporters passed near Tahrir Square during a protest march.
Four people were reported killed and dozens more were wounded.
One anti-Morsi protester says it escalated quickly.
"We were near to Tahrir Square next to Kasr el-Nil bridge and we heard gunshots and fireworks and there was an exchange of clashes between anti-Morsi protesters and a march that was heading to the U.S. Embassy."
Earlier Monday, Mr. Morsi's family spoke out against Egypt's military, accusing it of kidnapping him. The former president's son, Osama Morsi, threatened to use legal measures to gain his father's release.
"I sent a message to the international media, and civil society organizations and the United Nations to uphold the responsibility of the safety and security of the president, who is still the legitimate president. We are placing the responsibility of his safety upon everyone, and we don't exempt anyone from the responsibility. What happened is a complete crime of abduction and no less, and a perfect example of the kidnapping of the people's will and kidnapping an entire nation.''
At a news conference in Cairo, Osama Morsi said the family has not seen their father since July 3 when Egypt's military overthrew Mr. Morsi's democratically elected government.
Mr. Morsi's daughter, Shaimaa, also had harsh words for Abdel Fattah el-Sissi, the army commander and defense minister who played a central role in forcing Morsi from office.
"We hold responsible the leader of the bloody military coup and his group, the security and safety of the health of my father, the civilian and the president.''
Military officials say they have detained Mr. Morsi for his own protection and that he is in good health.
Mr. Morsi's Muslim Brotherhood has been holding near daily demonstrations in Cairo and across the country, demanding his release and reinstatement. He had served only one year of his term as Egypt's first democratically elected president following the removal of longtime leader Hosni Mubarak in 2011.
Egypt's military-backed interim leaders are pressing ahead with their road map for returning the country to democratic rule.
On Sunday, a panel of experts rewriting controversial parts of the suspended constitution met for the first time. Egypt's interim government has said it intends to hold new elections under a revised constitution early next year.