CAIRO – Five people were injured – one of them critically – when a roadside bomb hit a bus in Cairo's Nasr City district on Thursday, officials said.
The homemade device had been place near a bus stop and was detonated as passengers were getting off, a security source said.
A second bomb was found nearby and defused by an explosives ordnance team, the sourced added – and a third device was also being dealt with.
All three devices were in an area close to the King Fahd school complex.
Egypt’s military-backed interim government has vowed to fight "black terrorism" after Tuesday's deadly attack on a police compound in the city of Mansoura which killed 16 people and injured about 140.
It intensified its crackdown on the Muslim Brotherhood on Wednesday, formally listing the group as a terrorist organization.
The move gives the authorities the power to charge any member of the Brotherhood with belonging to a terrorist group, as well as anyone who finances the group or promotes it "verbally, or in writing."
The Brotherhood, which estimates its membership at up to a million people, was Egypt's best organized political force until this summer's crackdown. A political and social movement founded in 1928, it won five elections after the downfall of President Hosni Mubarak in 2011.
Reuters contributed to this report.
Related: Egypt security base suicide bomb kills 12, wounds 134