CAIRO – A former strongman of ousted President Hosni Mubarak's regime announced his presidential candidacy Friday, shaking up an already heated race that is emerging as a contest between two longtime rivals – former regime officials and Islamists who have surged in influence.

Omar Suleiman, one of the most powerful figures of Mubarak's regime, had said earlier this week that he would not run. But he said he changed his mind after hundreds of people rallied in Cairo to support a bid.

The announcement drew outrage from youth activists who spearheaded the popular uprising that toppled Mubarak last year and have since been disappointed by the continued influence of members of his ex-regime. Liberals and revolutionaries have been largely squeezed out of the presidential race. Some have vowed to boycott the May 23-24 balloting altogether.