CAIRO, July 27 (Reuters) - At least 70 people died on Saturday after security forces attacked supporters of deposed President Mohamed Mursi in Cairo, Muslim Brotherhood spokesman Gehad El-Haddad said, adding the toll could be much higher.

Al Jazeera's Egypt television station reported 120 had died and some 4,500 had been injured in the early morning violence on the fringes of a round-the-clock vigil being staged by backers of Mursi near a Cairo mosque. (Reporting by maggie Fick, Editing by Crispian Balmer)