Egyptian police say a bomb detonated outside a historic Cairo mosque in the crowded bazaar area frequented by tourists, wounding at least eight people.
Blood stains could be seen in the front courtyard of Hussein mosque, next to the famed Khan el-Khalili bazaar in Islamic Cairo.
Riot police had cordoned off the area and sniffer dogs could be seen as worshippers were being evacuated.
A security official said police were attempting to defuse a second bomb.
The official spoke on condition of anonymity because he was not authorized to speak to the press.