(CNN) -- Egypt's interim leader on Sunday issued a strong warning to supporters of ousted President Mohamed Morsy, state news said.
After a meeting of the National Defense Council, headed by interim President Adly Mansour, the Egyptian presidency issued the statement, calling on protesters to remain calm.
It urged them to end their "incitement and hateful speech against Egyptian citizens and state institutions and end their violations of the law and endangering the safety of citizens," the state-run Al-Ahram newspaper said.
It also reportedly said that the National Defense Council would watch developments closely and take action against anyone who violates the law.
The warning came on the heels of violent clashes in the nation's capital.
Dr. Mohammed Ali Sultan, chairman of Egypt's ambulance services, told CNN that 72 people had been killed in Nasr City, an area of Cairo the Muslim Brotherhood has made its base.
Morsy is backed by the Muslim Brotherhood, the Islamist group that was sidelined under longtime Egyptian leader Hosni Mubarak only to become the country's dominant political force after his forced exit in 2011.
According to that group, police fired live ammunition on protesters Friday and Saturday.
Yet the prosecutor general's office, state-run Nile TV reported early Sunday, said protesters initiated the clashes, firing live bullets on security forces.
Fresh clashes erupted early Sunday in Helwan, south of Cairo, between residents there and pro-Morsy protesters, reported state TV, citing witnesses.
Also Sunday, state-run EGYNews reported that an Egyptian delegation was granted permission Friday by the military to visit where Morsy is being held.
The former Muslim Brotherhood leader became Egypt's first democratically president in June 2012 but found himself at odds with the opposition before the military removed him from power and detained him this month.
He has not been seen publicly since the military forced him from office July 3.
The delegates, who represent human rights organizations, said Morsy is being held at an army facility at an undisclosed location.
They reportedly said Morsy declined to meet with them because their group did not include Mohamad Salim Al Awa, a former presidential candidate and Islamic scholar.
Instead, they met with Morsy's former chief of staff, Refa'a al-Tahtawi, and his secretary. Both men are being held along with Morsy.
The delegation recommended that the military hold Morsy in a known and specific location and allow him to communicate with his family and have representation of his choosing, EGYNews reported.
It also recommended the release of Morsy's staff unless the men are charged with a specific crime.
Morsy is being held in relation for a jailbreak that took place during Egypt's 2011 revolution but well before he came to power, state media reported.
Prosecutors have said the escape of Morsy and 18 other Brotherhood members, among others, was plotted by "foreign elements" including Hamas, the Islamic Palestinian Army and Hezbollah. The Muslim Brotherhood was named as a domestic group that cooperated with those who broke them out of prison.
Morsy -- who local media reports say was in prison for a single day without any formal charges against him -- is accused of escaping, destroying the prison's official records and intentionally killing and abducting police officers and prisoners.
CNN's Dana Ford, Greg Botelho, Hamdi Alkhshali and Ben Wedeman contributed to this report.