Egypt's former spy chief joins presidential race CAIRO (Reuters) - The intelligence chief of Egypt's deposed leader Hosni Mubarak formally joined the race for the presidency on Sunday, a last-minute entrance that raises the heat in a contest pitting former regime figures against newly-assertive Islamists. Omar Suleiman announced he planned to run on Friday, saying overwhelming public pressure had stirred his sense of soldierly duty. He had needed to collect the signatures of 30,000 eligible voters by Sunday's deadline in order to take part. Ecstatic supporters cheered behind lines of military police as Suleiman arrived at the office of the state election committee in Cairo. He then handed in his candidacy documents, state news agency MENA reported, citing a committee official. Committee General Secretary Hatem Bagato "acknowledged that the papers included certified backing from citizens above the minimum required, which is at least 30,000," the agency said. Suleiman, who Mubarak made vice president in the dying days of his three-decade rule, symbolizes that era's tough security regime, making him a figure of hate to the young liberals who spearheaded Mubarak's overthrow last year but a possible draw for some Egyptians hoping for an end to political instability. Supporters of the urbane, secretive 74-year-old jostled with the security forces protecting the building, causing some injuries and the main entrance was briefly closed. Late additions to the candidate line-up and efforts to exclude some frontrunners from the job have shaken up Egypt's first free presidential vote due to be held in May and June. Suleiman's arrival on the scene comes shortly after the Muslim Brotherhood, the Islamist movement long suppressed by his former boss, scrapped a pledge not to field a candidate and nominated its deputy leader Khairat al-Shater for head of state. The move has fuelled concern among liberals and many in Egypt's large Coptic Christian minority that the Brotherhood wants to monopolies the main institutions of state to push through a conservative Islamic agenda. Another candidate, ultraconservative Hazem Salah Abu Ismail, is fighting attempts to bar him from the vote because of documents suggesting his mother held foreign nationality. More than 21 candidates had submitted their registration papers by Sunday including Abu Ismail, former foreign minister and Arab League chief Amr Moussa and Mohamed Morsi, named this weekend as the alternative Brotherhood candidate in case Shater is forced to withdraw, the vote commission website said. The victor must steer the Arab world's most populous country out of more than a year of precarious military rule even as the economy languishes and citizens grow impatient for dividends from an uprising driven by outrage at poverty and corruption. The Brotherhood and other Islamists dominate parliament and a body drafting a new constitution that could curtail the broad powers enjoyed by decades of Egyptian presidents. Writing by Tom Pfeiffer; Editing by Andrew Heavens