Former Egyptian general intelligence chief Omar Suleiman on Sunday formally filed his presidential candidacy application with the Supreme Presidential Electoral Commission (SPEC).
Suleiman, who briefly served as ousted president Hosni Mubarak's vice-president during last year's Tahrir Square uprising, arrived at SPEC headquarters surrounded by supporters and a protective cordon of military police.
Although Suleiman had earlier declared that he would not be running, he is said to have changed his mind after having been urged by thousands of supporters – who staged pro-Suleiman demonstrations on Friday in the Cairo district of Abbasiya – to contest Egypt's first post-Mubarak presidential race.
According to regulations laid out by the SPEC, would-be presidential contenders must enjoy the support of at least 30 elected MPs, collect 30,000 citizens' signatures from at least 15 governorates throughout Egypt, or secure the backing of a political party that holds at least one seat in parliament.
The election will be held on 23 and 24 May. If no single candidate wins an outright majority, the two leading contenders will face each other in a runoff vote slated for 16 and 17 June.
Other prominent presidential hopefuls to file candidacy applications on Sunday included rights lawyer Khaled Ali and leading Muslim Brotherhood member Mohamed Morsi.