CAIRO (AP) — A former deputy of ousted President Hosni Mubarak announced his presidential candidacy on Friday, shaking up an already heated race that is emerging as a contest between former government officials and Islamists who have surged in influence.

The deputy, Omar Suleiman, was the chief of intelligence under Mr. Mubarak and one of the most powerful figures in his government. Mr. Suleiman had said this week that he would not run. But he said he changed his mind after hundreds of people rallied in Cairo to support him.

The announcement drew outrage from youth activists who spearheaded the popular uprising that toppled Mr. Mubarak last year and have since been disappointed by the continued influence of members of his former government. Liberals and revolutionaries have been largely squeezed out of the presidential race. Some have said they will boycott the election on May 23 and 24.

Mr. Suleiman, who appeared on television on Feb. 11, 2011, to announce that Mr. Mubarak would step down and hand power to the country’s military leaders, served as Egypt’s intelligence chief for 18 years at a time when the government was accused of abusing the human rights of dissenters.