Egypt's National Defence Council has warned supporters of deposed president Mohamed Morsi that security forces would take "decisive and firm" action if protesters overstepped their rights, as thousands stood their ground at multiple demonstrations across the country.
The council called on protesters "not to exceed their rights to peaceful, responsible expression of their opinions", warning that they would face "decisive and firm decisions and actions in response to any violations".
Morsi's supporters responded defiantly, calling for protests at "security administration buildings" on Monday night, followed by a "million-man march" on Tuesday. The group organising the protests, led by the Muslim Brotherhood, urged Egyptians to "go out into the streets and squares to regain their freedom and dignity."
The warning from the council, which includes interim president Adly Mansour, army chief General Abdel-Fattah al-Sisi, the prime minister and interior minister, came in a statement published by state news agency MENA on Sunday.
The council also called on Morsi loyalists gathered at two sites in Cairo to "immediately announce their clear and categorical rejection of violence in all forms, and the immediate cessation of violence, terrorism and the verbal and physical abuse of citizens".
The statement came after at least 72 Morsi supporters were killed in violence at the Rabaa al-Adawiya protest site in Cairo early on Saturday.
The protesters accused security forces of using live ammunition against unarmed demonstrators, but the interior ministry said forces had fired only tear gas.
On Sunday, the interim presidency said it was "saddened" by the deaths but described Rabaa al-Adawiya as a "terror-originating spot" and said the bloodshed came in the "context of terrorism".
Earlier, in a thinly veiled warning to pro-Morsi protesters, the country's interim interior minister pledged to deal decisively with any attempts to destabilise the country.
"I assure the people of Egypt that the police are determined to maintain security and safety to their nation and are capable of doing so," Mohamed Ibrahim told a graduation ceremony at the national police academy.
"We will very decisively deal with any attempt to undermine stability," said Ibrahim, who is in charge of the police.
Al Jazeera's Hoda Abdel Hamid, reporting from Cairo, said his comments come off the back of events over the past week, beginning with the "popular mandate" given to the army to "fight terrorism".
"By association, the police also got the same mandate. We've already seen them co-operating on the ground, and we've already heard they will be co-operating together in the coming days."
However, in one of the first signs of doubt from within the interim cabinet installed after the military takeover, Deputy Prime Minister for Economic Affairs Ziad Bahaa El-Din said the government must not copy the "oppressive and exclusionary policies" of its foes.
"Our position must remain fixed on the need to provide legal guarantees not only for the members of the Brotherhood, but for every Egyptian citizen. Excessive force is not permitted," El-Din wrote on Facebook.
In another sign of unease, the Tamarud youth protest movement, which mobilised millions of people against Morsi and has fully backed the army, expressed alarm at an announcement that the interior minister was reviving the feared secret political police shut down after former president Hosni Mubarak was toppled.
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Earlier on Sunday, supporters of Morsi pledged to press ahead with their protests, a day after the bloody clashes at in Cairo.
Sporadic violence was also reported nationwide overnight, including in the Suez Canal city of Port Said, where two people were killed.
Gehad El-Haddad, a spokesman for the Brotherhood, said demonstrators were angry but "hugely defiant" after Saturday's deaths.
"There are feelings of agony and anger, but also a very strong feeling of determination," he said. "People are hugely defiant. [...] For us, if we die, we meet our creator and we did so for a just cause. Either we die or we succeed."
Pro-Morsi protests continued in nine cities, including mass sit-ins at Cairo's Rabaa al-Adawiya and Nahda squares, until late on Sunday night.