At least six dead in four attacks that mark apparent escalation of insurgency waged by Islamist extremists

This article is more than 6 years old

This article is more than 6 years old

Cairo was rocked by four explosions on Friday that killed at least six people, injured 80 and severely damaged artefacts inside a major Egyptian museum.

The first and largest explosion was a suicide bomb that struck Cairo's police headquarters early on Friday morning – the eve of the third anniversary of the 2011 uprising that toppled former president Hosni Mubarak.

Two smaller blasts occurred near a metro station and a police station in west Cairo. The first killed one person and injured four after a passing driver threw a grenade at police vehicles, officials said. No casualties were reported from the second blast.

The fourth blast went off outside a cinema on Haram Street, which leads to the Giza pyramids, as a police convoy passed on its way back from clashes with Morsi supporters.

The explosions mark an apparent escalation of an insurgency waged by Islamist extremists since the ousting of Mohamed Morsi last July, which has killed more than 100 police officers and soldiers. It follows an audio warning released overnight by Egypt's most prominent extremist group, Ansar Beit al-Maqdis, which previously claimed responsibility for a failed attack on Egypt's interior minister, and last month's bomb at a northern police headquarters which killed 16 officers.

A man carries an Egyptian police officer to an ambulance after the car bombing in central Cairo. Photograph: Khalil Hamra/AP

The group has repeatedly condemned the police, who were the target of three of Friday's explosions, for the post-Morsi crackdown on Islamists.

More violence is feared on Saturday, after the prime minister, Hazem Beblawy, called on Egyptians to use the third anniversary of the 2011 uprising to march in support of the police – while Ansar Beit el-Maqdis warned Egyptians to stay away from public squares.

The suicide bomb occurred shortly after 6.30am, about half an hour after the closure of a nearby security checkpoint, according to Mahmoud Abdel Sattar, a 27-year-old sergeant on duty on the third floor of the building.

A police officer stands in front of the Egyptian police headquarters following a blast in Cairo. Photograph: Khalil Hamra/AP

"A big truck exploded outside the fence – it didn't get inside the [forecourt of the] security headquarters itself," Sattar said, while being treated for a head wound at a nearby hospital. "After the explosion, a white private car with four passengers started shooting on the buildings as well."

Sattar was hit by falling masonry. "There was gunfire between the two sides. Everyone started running and there were a lot of injuries."

Other survivors reported hearing gunfire after the explosion. "I heard the explosion, then the ceiling fell in, and after that I heard shooting," said police conscript Ahmed Hussein, who was injured by the debris. "My colleague went outside to see what was happening, but ran back inside because of the gunfire."

The blast caused a large crater outside the building that quickly filled with water. An official at the scene said it was four metres deep.

Emergency workers gather at the Egyptian police headquarters after the blast in central Cairo. Photograph: Khalil Hamra/AP

The immediate aftermath was chaotic, said Abdelrahman Mohsen, a 27-year-old furniture maker who arrived on the scene shortly after the explosion, and helped to carry away the casualties.

"I saw at least four bodies on the floor, and then we carried four more," said Mohsen, who could not confirm if the victims were dead. "There were a lot of police conscripts going inside and trying to find their friends, and there was masonry falling down on them in front of the building."

The explosion, heard from several miles away, smashed windows, collapsed house walls and warped the shutters of shopfronts. It severely damaged the collection of the Islamic Museum, which stands opposite the targeted building, after debris crushed much of the museum's glass and ceramic artefacts.

The attacks may strengthen the hand of Egypt's current government, which has justified its ongoing crackdown on dissent as an essential means of combatting terrorism. More than 1,000 Morsi supporters have been killed in the crackdown, and thousands more arrested since July.

Officials and almost all media outlets say Morsi's Muslim Brotherhood is a terrorist group that is behind all attacks on the Egyptian state – but have thus far provided no evidence of their involvement.

Onlookers at the site of the first blast loudly backed the government's narrative, immediately blaming the Muslim Brotherhood for the attack.

"The people demand the execution of the Brotherhood," chanted a crowd of bystanders, some of whom carried pictures of General Abdel Fattah al-Sisi, the army chief who ousted Morsi.

Two mobs attacked a van suspected by some of containing members of the Brotherhood.

However, David Barnett, an analyst specialising in the insurgency and a research associate at the Foundation for Defence of Democracies, said the evidence for Brotherhood involvement in the attacks was tenuous at best. "While Ansar Beit el-Maqdis has acknowledged having former members of the Muslim Brotherhood within its ranks, these are former members who specifically left because they were upset that the Muslim Brotherhood was not implementing violent jihad," he said.

Reuters reported that about 2,000 Morsi supporters clashed with security forces in Cairo after Friday prayers. A Muslim Brotherhood-led coalition has held near-daily demonstrations against the overthrow of Morsi and the recent vote on the country's rewritten constitution.

Morsi supporters, Sisi supporters, and pro-democracy activists opposed to both men's authoritarianism all plan to mark Saturday's third anniversary of the 2011 uprising with rival demonstrations.