Supporters of ousted Egyptian president Mohammed Mursi defiant
Wave of rallies called to reject the military's ousting of Islamist president as international community waits to see how the army will respond
Egyptian security forces clashed with supporters of deposed President Mohammed Mursi in Cairo as protests broke out across the country following the Muslim Brotherhood's call for a "Friday of Rage" to protest against his ouster by the military.
At least three protesters were shot dead outside the Republican Guard barracks in Cairo where the deposed president is being held, security sources said.
Egypt's first freely elected president was toppled on Wednesday in what his Islamist supporters call a military coup.
Television footage showed Mursi supporters with what appeared to be shotgun pellet wounds.
The army denied blame. An army spokesman said troops did not open fire on the demonstrators and soldiers used only blank rounds and teargas to control the crowd. It was unclear whether security forces units other than army troops were also present.
In the Suez city of Ismailia, soldiers fired into the air as Mursi supporters tried to break into the governor's office. Thousands of Islamists took to the streets of Alexandria and Assiut to join protests.
Speaking to the supporters at a Cairo rally, the leader of Brotherhood, Mohamed Badie, said protesters will remain mobilised until Mursi was reinstated as president.
As a military helicopter hovered low over the crowd, Badie called on the army not to fire on its own people and said that demonstrations were stronger than tanks.
"Our bare chests are stronger than bullets," he said.
He had earlier called for mass rallies to continue until the Brotherhood could carry Mursi "on our shoulders".
Shortly before the rallies, about a dozen low-flying military jets screeched across Cairo, a day after they staged a parade leaving a trail of smoke in the shape of a heart in the sky.
Egyptian troops were "on alert" in the Sinai Peninsula, a military spokesman said, but he denied a report by the state-owned al-Ahram newspaper that a state of emergency had been declared in Suez and South Sinai provinces.
How the army deals with any trouble will help determine future support for Cairo from the United States and other international powers.
Outside the Rabaa al-Adawiya mosque in a Cairo suburb, the army deployed extra armoured vehicles several hundred metres from makeshift barricades.
Hoda Ghaneya, a leading female figure in the Brotherhood, said she and two of her sons accompanying her at a Cairo rally were ready to sacrifice themselves to the cause.
"We will die not as a sacrifice for Mursi, but so the Egyptian people recover their freedom," she said.
Mursi's political opponents insist there was no coup. Prominent liberal leader Mohamed ElBaradei defended the military's intervention. "We asked the army to intervene because the other option was a civil war. We were between a rock and a hard place, and people need to understand that," the former UN nuclear watchdog chief told the BBC.
Concern that the generals have carried out a military coup against Egypt's first freely elected leader has left Washington reviewing the US$1.5 billion in mostly military aid it annually gives Egypt. US law bars aid for countries where the military has toppled an elected government in a coup. The US has so far avoided using that label.
The African Union, after a meeting in Addis Ababa to discuss the crisis, suspended Egypt from the union "until the restitution of constitutional order".
After a busy day of diplomacy by concerned Obama administration officials, the Egyptian armed forces command issued a late-night statement guaranteeing rights to protest and free expression, and pledging not to pursue arbitrary measures against any political group.
The uncontroversial phrasing belied a busy 24 hours since the military chief suspended the constitution, detained Mursi and oversaw the swearing in of the chief justice of the constitutional court as interim head of state.
Adly Mansour, the constitutional court chief justice sworn in as interim head of state on Thursday, has held out an olive branch to the Brotherhood, but a senior official in the Islamist movement said it would not work with "the usurper authorities".
In Hong Kong, the Travel Industry Council's executive director Joseph Tung Yao-chung said all local group tours to Egypt except one would be cancelled until July 20.
The pilgrimage tour organised by Holyland Travel to Jordan and Egypt will proceed as planned on Sunday.
Additional reporting by Associated Press, Staff Reporter