A large blast ripped through a security headquarters in central Cairo early on Friday, state TV reported. The explosion at the Cairo Security Directorate, in Bab El-Khalk district, smashed the building's windows andstripped off parts of its facade . Police have cordoned off the area and ambulances rushed to the scene to transport the wounded. No official estimate of casualties was immediately available. TV footage showed dense smoke billowing from the building after the blast that took place around 6:30 CLT. http://english.ahram.org.eg/News/92374.aspx