Cairo (CNN) -- Egypt's interim leader vowed Thursday to fight those who attempt to steer the country into chaos even as supporters of deposed President Mohamed Morsy called for renewed protests against the military-installed government.
Interim President Adly Mansour's speech came amid fears of widening violence, with dozens reportedly killed and thousands more injured in clashes between Morsy's supporters and those opposed to his rule.
Mansour blamed the violence on those bent on destabilizing the country and pledged to restore security and stability.
"We will not be frightened or be dismayed, and there will be no compromising or complacency with those who are killing the innocent," he said in his first televised address since Morsy was forced from office on July 3 by the military. "We will battle to the end to bring security. We will maintain the revolution. The past will not return."
Mansour, a veteran judge before he was tapped as the country's interim leader earlier this month, said his country was going through a "decisive phase."
"Some want to push towards the unknown path, and we want it to be towards the best path," he said. "Some want it to be the start of the chaos and we want it to be the start of stability."
But even as Mansour called for a national reconciliation, the deep divisions were on display with rival rallies being called for Friday in the capital of Cairo.
Supporters of Morsy, who is backed by the Muslim Brotherhood, were being urged to take to the streets as part of a "Breaking the Coup" rally, while Morsy's opponents are calling on people to turn out to support the new government and protest "against terrorism."
In Cairo, thousands of Morsy's supporters have been holding a sit-in at a square near Rabaa al-Adawiya mosque. A short distance away, Morsy's opponents have held rallies at Tahrir Square -- considered ground zero for the 2011 popular uprising that ousted Hosni Mubarak.
The U.S. Embassy in Cairo warned personnel and American citizens to limit travel during the protests.
"The Embassy suggests that U.S. citizens limit their movements, avoid areas prone to gatherings, and immediately vacate any area where crowds are gathering," according to a statement. "It is possible that additional demonstrations and acts of civil disobedience may develop elsewhere in Egypt."
The Friday protests fall on the Tenth of Ramadan, a revered day on the Islamic calendar. The anniversary is likely to galvanize both sides.
The military warned demonstrators "not to deviate from peaceful means of expression or resort to violence or vandalism," according to a statement released to the state-run al-Ahram Online news agency.
The statement also warned: "...Whoever does not abide peacefully is only exposing his life to danger and will be dealt with according to the law."
The military has come under fire for what human rights groups have described as heavy-handed dealings with protesters, while others have blamed Morsy's supporters and opponents for inciting violence.
In North Sinai, where the military has been battling militants, gunmen opened fire Thursday at a police vehicle, according to al-Ahram.
At least three police officers were reportedly injured in the attack, which comes amid an increase in violence in the region.
CNN's Salma Abdelaziz reported from Cairo, and Hamdi Alkhshali from Atlanta.