CAIRO (UPDATE )- At least six people were killed on Friday when a four-storey residential building collapsed in Cairo's Shubra neighbourhood, a security source said Saturday. The dead included two children and a man believed to be in his forties. Rescue workers pulled out seven survivors, four of whom were injured, and at least six people were unaccounted for, the source told Reuters, adding that workers were carrying out repairs on the first floor at the time the building collapsed. Two of the workers are among the six people still unaccounted for and believed trapped under the rubble. Building collapses are common in Egypt because of lax building standards and poor maintenance.