(CBS News) - Egypt's Muslim Brotherhood called for a wave of protests Friday, furious over the military's ouster of its president and arrest of its revered leader and other top figures, and there were reports of violence as the protesters clashed with state security forces.
There were reports that as many as three people had been killed in clashes between supporters of president Mohammed Morsi and military forces outside the headquarters of the Republican Guard, where Morsi was reportedly being held.
A BBC reporter at the scene said he witnessed security forces open fire with live ammunition in the direction of protesters, killing at least one person. Pan-Arab network al-Arabiya reported three people had been killed. Egypt's state television network, controlled by the interim government and the military, refuted the claims, quoting security officials as saying nobody had been killed in the clashes outside the Republican Guard building.
Video from the scene showed demonstrators with injuries, but no fatalities.
A hardline salafist political group said in a statement online that 40,000 supporters of the ousted leader had set out to march from a mosque about 3 miles away to try and "liberate" Morsi.
The first coordinated assault by Islamic militants since Morsi's ouster, however, came in the lawless Sinai Peninsula. Masked assailants launched coordinated attacks Thursday with rockets, mortars, RPGs and anti-aircraft guns on el-Arish airport, where military aircrafts are stationed, as well as the Central Security camp in Rafah and five military and police posts.
The military and security forces returned the fire. Military helicopters flew over the area.
Egypt indefinitely closed its nearby border crossing into the Gaza Strip after the assault, sending 200 Palestinians back into Gaza, said Gen. Sami Metwali, director of Rafah passage.
Extremist Islamic militants have gained strength in the Sinai over the past two years since a security breakdown that accompanied the 2011 uprising that forced Morsi's predecessor, Hosni Mubarak, from power. Egypt's military and police have been battling to contain them.
U.S. cautious during Egypt's political transition
U.S.-Egypt relationship uncertain after Morsi's ouster
Egypt's temporary president sworn in
The task will be a difficult one -- both logistically and politically -- as the peninsula is vast, largely out of the control of the Egyptian authorities in some parts, and having just ousted a democratically elected president, it is an awkward time for the military to contemplate an all-out offensive against hardliners in the region.
Military officials denied reports that an official state of emergency had been declared in south Sinai on Friday, but added that troops in the area remained on alert.
The military forced Morsi out Wednesday after millions of Egyptians turned out in four days of protests. After its top leaders were targeted with arrest warrants, the Muslim Brotherhood hotly rejected an appeal by the military to take part in forming a new regime.
A military statement late Thursday appeared to signal a wider wave of arrests was not in the offing. A spokesman, Col. Ahmed Mohammed Ali, said in a Facebook posting that that the army and security forces will not take "any exceptional or arbitrary measures" against any political group.
The military has a "strong will to ensure national reconciliation, constructive justice and tolerance," he wrote. He spoke against "gloating" and vengeance, saying only peaceful protests will be tolerated and urging Egyptians not to attack Brotherhood offices to avert an "endless cycle of revenge."
The Brotherhood charged the military staged a coup against democracy and said it would not work with the new leadership. It and harder-line Islamist allies called for a wave of protests Friday, naming it the "Friday of Rage," vowing to escalate if the military does not back down.
Brotherhood officials urged their followers to keep their protests peaceful. Thousands of Morsi supporters remained massed in front of a Cairo mosque where they have camped for weeks, with line of military armored vehicles across the road keeping watch.
"We declare our complete rejection of the military coup staged against the elected president and the will of the nation," the Brotherhood said in a statement, read by senior cleric Abdel-Rahman el-Barr to the crowd outside the Rabia al-Adawiya Mosque in Cairo.
"We refuse to participate in any activities with the usurping authorities," the statement said, while urging Morsi supporters to remain peaceful. The Rabia al-Adawiya protesters planned to march Friday to the Ministry of Defense.