Cairo rocked by deadly bomb attacks

At least five people have been killed in three bombings in the Egyptian capital, the latest in a series of attacks that have rattled the public and undermined confidence in the interim government.

The first and deadliest explosion tore through the security directorate in downtown Cairo, killing four people and injuring more than 70, according to the health ministry. Officers at the scene said it was a suicide car bombing.

The blast left a deep crater in the street, and was large enough to shatter windows in shops hundreds of meters away. It also caused extensive damage to the Islamic antiquities museum across the street.

Witnesses said they heard gunshots before the explosion. "It was around 7am this morning. I heard shots and then the ground shook, the windows shattered," said Mohamed Taher, sweeping broken glass outside his cafe near the bomb site.

The bombing bore many of the hallmarks of Ansar Bait al-Maqdis, a Sinai-based armed group that has carried out numerous high-profile attacks over the past year, most recently a December 24 bombing outside a police station in Mansoura that killed 14 people.

The group released an audio message on Thursday night, hours before the bombing, that threatened further attacks on police and army targets.

No group has said it carried out the attacks, but onlookers were quick to blame the Muslim Brotherhood, which ruled Egypt for a year until Mohamed Morsi was removed by the army from the presidency in July.

"The people demand the execution of the Muslim Brotherhood," a crowd of several hundred people chanted outside the security directorate. Many of them held posters of General Abdel Fattah el-Sisi, the popular defence minister who led Morsi's removal.

The Brotherhood issued a brief statement on Friday morning saying that it "strongly condemns the cowardly bombings in Cairo… and demands swift investigations".

'All squares will be protected'

About three hours after the first explosion, there was a second blast at a metro station in Dokki, on the west bank of the Nile. Police said it was caused by a bomb hidden in a bag. One security officer was killed, according to the health ministry, and at least eight others injured.

A third explosion outside a police station in Giza caused no casualties.

The bombings come one day before the third anniversary of Egypt's 2011 revolution, which removed the longtime president, Hosni Mubarak, from power. The interim government has asked supporters to come down to Tahrir Square and other

"[This] is a desperate way to spread terror among the people," Mohamed Ibrahim, the interior minister, said on state television. "All squares will be protected, and the plans for January 25 are fine. I urge people not to fear anything."

Still, there was widespread anger towards the government at the scene of the first bombing, where many people said the interior ministry has not done enough to restore security. "How is this still happening? The government has had six months and they can't stop the terrorism," asked Umm Hasan, standing a few hundred meters away from the site.

Attacks have become increasingly routine in Cairo over the past few months. Last week, a small bomb exploded outside a courthouse in Imbaba, a neighbourhood in western Cairo, and five people were injured last month in an attack on a bus in Nasr City.Al Jazeera