MEXICO CITY, Sept 14 (Reuters) - Leftist protests forced Mexican President Vicente Fox to abandon plans to lead a traditional ceremony in the capital on Friday, the eve of independence day, the Interior Minister said. Fox, targeted by leftists angry at what they say was fraud at July's presidential election, will instead hold the highly-symbolic cry of independence in the central town of Dolores Hidalgo, minister Carlos Abascal told reporters on Thursday. The ceremony, known as "el grito", takes place every Sept. 15 in the central Zocalo square but leftists have vowed to demonstrate against conservative Fox in the plaza.