Leader returns from exile to mark founding of Palestinian Islamist group at gathering that Fatah rivals are due to attendThe Hamas leader Khaled Meshaal is to lead a rally in Gaza on Saturday to mark the founding of his Islamist group and celebrate what he claims is "victory" over Israel.At least 200,000 Palestinians are expected to attend the outdoor event, which is likely to be used by Meshaal to promote Hamas's growing stature in the Arab world and push the case for reconciliation with its secular political rival, Fatah.Thousands of supporters, many holding aloft Hamas's green flag, gathered on rain-sodden wasteland ahead of the rally.