Five people were injured on Thursday when a bomb exploded near a bus in the Egyptian capital, two days after a blast at a police station in the Nile Delta city of Mansoura killed 14 people.
The explosion happened in Cairo's Nasr City neighbourhood, in front of Al-Azhar University. Ambulance workers said one of the injured passengers was in critical condition.
Police said the bomb was a small homemade device planted in the street. It blew out the windows of the bus, but caused little damage to the surrounding area, and the driver was able to move the bus after police cordoned off the area.
“We defused two other bombs in the area, which were meant to detonate by remote,” said an officer at the scene, speaking on condition of anonymity.
There was no immediate claim of responsibility for the bombing.
Cairo has seen several homemade bomb attacks in recent months, though they have typically targeted the security forces instead of civilians. Last month Mohamed Mabrouk, a lieutenant colonel in the state security service, was killed near his home in Nasr City. The interior minister himself survived an assassination attempt in the neighbourhood in September.
Thursday’s blast came hours after the interim government labelled the Muslim Brotherhood a “terrorist organisation" and froze the assets of charities linked to the group.
A Sinai-based group, Ansar Bayt al-Maqdis, claimed responsibility for the Mansoura bombing in a statement posted online. Armed groups have killed dozens of soldiers and police officers on Sinai over the past few months.
But the government nonetheless pinned the blame on the Brotherhood, though it has presented no evidence tying the group to the attack. Authorities are facing mounting criticism that they have not done enough to restore security.
“The police and the army, they are the biggest powers in the country, and they have one responsibility, to protect the people,” said Tarek Ezzedine, who witnessed Thursday's explosion. “They need to do their job.”
Al-Azhar has for months been the site of near-daily protests by student supporters of President Mohamed Morsi, who was ousted by the army in July. The university, and the bombing site, are down the road from Rabaa al-Adawiya square, one of two locations where hundreds of pro-Morsi protesters were killed by police in August.
Hany Abdellatif, a spokesman for the Interior Ministry, said the bombing was meant to instill fear ahead of a January referendum on Egypt’s new constitution, and indeed bystanders at the scene on Thursday questioned whether authorities will be able to secure the vote.
“The Muslim Brotherhood and April 6, they want terror and chaos 24 hours a day,” said Amr Shobaki, a local resident, referring to an activist group whose founder was sentenced to prison on Sunday for organising an unlicensed protest. “Where is the government? What are they doing?”