A string of four bombings struck Greater Cairo on Friday, killing at least six people and injuring dozens of others, on the eve of the anniversary of the 2011 uprising that toppled Hosni Mubarak.
The wave of attacks began when a car bomb ripped through a police compound in central Cairo, killing four and injuring 76 others, according to the health ministry.
Hours later in Giza, one person was killed when a primitive bomb exploded after being thrown at a moving police vehicle near a metro station, deputy Giza security chief Mahmoud Farouk told state TV. At least 11 others were reportedly wounded in the attack.
In a third blast, a small bomb went off later on Friday morning at a police station in Talbiya district, also in Giza, near the pyramids. The attack did not cause any casualties, the interior ministry said.
Later on in the afternoon, an explosion near a cinema theater in Giza’s Haram caused at least one fatality.
"It's a vile, desperate attempt by evil terrorist forces to disrupt the success Egypt and its people have achieved in the [transitional] roadmap and the passing of the new constitution," Prime Minister Hazem El-Beblawi commented, in reference to the Cairo bomb.
The first explosion, which hit the Cairo Security Directorate in Bab El-Khalk district, blew out the windows of the building and stripped off parts of its façade.
"I was manning the building along with my fellow conscripts shortly after dawn when the explosion took place," police conscript Ahmed Ibrahim who was injured in the blast told Al-Ahram Arabic from his hospital bed.
"I didn’t believe I had survived until I was pulled out from under the rubble."
According to a statement by the interior ministry, a car exploded at the cement barriers surrounding the main Egyptian police headquarters in central Cairo. Initial investigations showed a remotely-detonated car bomb was behind the blast, a security official told Ahram .
Three attackers parked the explosive-laden vehicle and fled in another before it was let off, South Cairo senior prosecutor Ismail Hafiz said, denying that a charred body found near the exploded vehicle was that of a bomber.
The attack took place at around 6:30am local time and was heard across several parts of the capital.
TV footage showed wrecked floors of the multi-storey building and a damaged facade of the nearby Museum of Islamic Art. The minister of state for antiquities told journalists in a statement after touring the site that some artefacts and items inside the museum had also been damaged. He said the 19th-century museum building, which was recently rennovated in a multimillion-dollar project, will need to be "rebuilt."
Photos show that the building's roof has caved in, floors are covered with shattered glass and wood debris, and the display cases housing the museum artefacts have been smashed.
The blast also wrecked a nearby historical book house, damaging several rare papyri and manuscripts housed in the building.
An Ahram Online reporter at the scene of the blast said she saw a badly mangled vehicle stained with blood parked in front of the police compound. Some of the building's walls have collapsed and a gaping crater was left in the ground.
The attack has also caused water pipes in the area to explode, and vacuum excavators were sent to remove the water pooling in the street, the reporter added.
An Al-Qaeda-inspired group, Ansar Beit Al-Maqdis or (Partisans of Jerusalem), has claimed the major bombing at the Cairo police compound. The group, which has claimed the deadliest militant attacks since Morsi's ouster in July, has warned Egyptians in an audio statement against taking to the streets on Saturday, the third 25 January revolution anniversary.
The group has also claimed a failed assassination attempt on the interior minister in Cairo in September, and a December bomb attack that killed 16, mostly policemen, at a security headquarters in the Nile Delta city of Mansoura.
The violence came only one day ahead of the third anniversary of the 2011 uprising that toppled president Hosni Mubarak, raising the spectre of further violence. Police have been set to deploy around the country to secure key security sites.
In a statement, the president pledged to "severely punish" those involved in "planning, financing, inciting, participating in or executing" such attacks, saying that tampering with state security is a "red line."
He added that Egypt had quashed an Islamist insurgency that raged in the 1990s and "would relentlessly rout [terrorism] and root its culprits out.
"Such terrorist attacks will only unite the will of Egyptians to move forward towards achieving the goals of the 25 January and the 30 revolution … and to carry out Egyptians' upcoming roadmap." the Egyptian presidency added.
A spate of recent explosions in densely populated areas has raised fears that militant activity in the border Sinai Peninsula, which has spiked since Morsi's removal, would take its toll on other parts of the country.
"They don't want the people to celebrate," Interior Minister Mohamed Ibrahim told reporters while inspecting the explosion site in Cairo, adding that he was certain that "millions would take to the streets" on Saturday to celebrate the revolution nonetheless. He added that the "despicable attack" would not hamper police "in their fierce war against black terrorism."
After the explosion, large crowds of onlookers gathered at the Cairo site, chanting slogans demanding the "execution" of the Muslim Brotherhood movement and of ousted president Mohamed Morsi.
The Brotherhood was designated a terrorist organisation by the cabinet in December, although it has persistently denied any links with ongoing terrorist attacks.
The group's official English language Twitter account has denied responsibility for the Friday attacks, saying that it "strongly condemn(s) cowardly bombings in Cairo, express(es) condolences to families of those killed, demand(s) swift investigations."
Tensions were simmering in other parts of the country on Friday as violent clashes broke out later in the day between supporters of ousted president Mohamed Morsi, and police and opposing civilians in several governorates. At least 14 were killed in the clashes.
Violence also flared during protests in Alexandria, Giza, and Ismailia.
On Thursday, gunmen on motorbikes had killed five policemen at a checkpoint south of Cairo.
A bomb also exploded outside a Cairo court just before polls were to set to open in last week's constitutional referendum, leaving no casualties.