Editor's note: This story was updated at 11:15 a.m. to include an additional bombing and fatality.
An explosives-laden truck was detonated in front of the Cairo security headquarters around 6:30 a.m., killing four police officers. Two small explosions followed in the western part of the capital several hours later, killing one police officer, and were likely caused by small improvised explosive devices, said a police official. A fourth bomb, apparently planted on a road and detonated as security officials drove by, killed one person. Dozens of people were wounded in the attacks, which left heaps of rubble at the foot of the crumbling security headquarters facade and air conditioning units dangling out of broken windows.
With the largest bombing carried out on a Friday morning, the start of the weekend, when Cairo's streets are largely empty, the bombings appeared intended to target police while largely avoiding civilian casualties. That fits the pattern of many previous attacks against Egyptian security forces, which have been growing since the popularly backed coup that removed former president Mohamed Morsi, and the subsequent violent crackdown on the former Muslim Brotherhood leader's supporters.
The apparently coordinated bombings come amid deep polarization in Egypt as the military-led transition process moves forward. Egyptians approved a new Constitution in a referendum last week, and dates for presidential and parliamentary elections are to be announced soon, with many Egyptians urging Army chief Abdel Fattah al-Sisi to run for president. But many Egyptians opposed the military coup and subsequent transition, and the bombings are stoking fears that the violent backlash many warned of after police killed hundreds of Morsi supporters in August had become a reality.
Interior Minister Mohamed Ibrahim called the bombing a “vile terrorist act” and vowed that police would continue their “war on terrorism.” Mr. Ibrahim survived an assassination attempt in September.
No group has yet claimed responsibility for today's attacks. But bystanders at the site of the first bombing in Cairo this morning, and others throughout the capital, were quick to blame the Muslim Brotherhood. The government has labeled the Brotherhood a terrorist organization, and government officials regularly use such language to refer to the group. Officials initially accused the Brotherhood of a Dec. 24 bombing that killed 16 people, even though a separate organization claimed responsibility for the attack.
The Brotherhood, which renounced such violence decades ago, condemned the attack in a message posted on its English-language Twitter feed. Peaceful revolution against a "fascist military coup is the only is the only path chosen by Egyptians to restore their freedoms," the message read, adding that the group holds the "coup authorities" responsible for deteriorating security and failures to apprehend the perpetrators of previous bombings.
An apparently impromptu crowd gathered at the debris-littered site of the bombing soon after the blast, demonstrating angrily against the Islamist organization. “The people demand the execution of the Brotherhood!” they chanted. Others declared the bombers to be infidels.
“This is black terrorism. It's the Brotherhood,” said one area resident as she stood at a police cordon and watched security forces attempt to drain the water from the blast's crater in the street. “They began this terrorism, and they're destroying our country.”
The woman, who refused to give her name, said she awoke in her nearby apartment to the sound of the blast and came out to find “everything destroyed.” Another woman wandered through the site, stepping over bits of broken glass, twisted metal, and shredded paper with tears running down her cheeks.
Anger at the US
Many in the crowd were also angry at the United States. One man raised a picture of Gen. Sisi, who deposed Morsi, and railed against the US for “supporting terrorism and the Muslim Brotherhood.” Some focused their anger at the US on foreign reporters, and several journalists were assaulted by angry crowds.
The blast also hit the Museum of Islamic Art across the street from the security headquarters. The building's facade was heavily damaged, and damage was visible inside the building. Egypt's antiquities minister visited the museum two hours after the blast and said there had been extensive damage to antiquities housed in the museum, which had recently been renovated.
The bombings were the latest attacks in an insurgency that has grown since the military ousted Morsi and security forces killed more than 1,000 of his supporters. Since then, the bombings that were relatively common in Egypt's lawless Sinai peninsula have spread to the rest of Egypt, with small attacks on police checkpoints and police stations giving way to larger bombings.
The Sinai-based militant group Ansar Bayt al-Maqdis (Supporters of Jerusalem), which has expressed admiration for Al Qaeda, has claimed responsibility for a number of attacks. Those include the car bomb assassination attempt on the interior minister last fall, as well as the deadly December bombing in the Nile Delta city of Mansoura.
Police were on high alert throughout the capital after the attacks, and many Egyptians expressed worry about what will happen Saturday, the anniversary of the 2011 uprising against Mr. Mubarak. Morsi supporters had called for large protests Friday afternoon.