A commission will investigate circumstances surrounding the fighting . Egypt 's military council declared three days of national mourning . Egypt 's health ministry says three people were killed in clashes . One witness says police did not step in when fighting broke out .
A committee will investigate circumstances surrounding the fighting . Egypt 's military council declares three days of national mourning . Egypt 's health ministry says 74 people were killed in clashes . One witness says police did not step in when fighting broke out .