CAIRO - Egyptian leftist Hamdeen Sabbahi on Saturday submitted the documents required to run in next month's presidential election, in which he is likely to be the only rival to former army chief Abdel Fattah al-Sisi.
Mr Sabbahi is currently General Sisi's sole challenger after lawyer Mortada Mansour announced he was withdrawing his candidacy, although there is another day before the expected end of the registration period.
Gen Sisi, who is riding a wave of popularity after ousting Islamist president Mohamed Mursi last July amid massive street protests, is widely expected to win the May 26 to 27 election.
"With God's will, we will wage a great and victorious battle," Mr Sabbahi told supporters after submitting his candidacy to the electoral commission.
Mr Sabbahi has surpassed the 25,000 signatures from citizen supporters required to officially register his candidacy, gathering 31,100 signatures from 17 provinces, according to his campaign team.
Mr Sabbahi was accompanied by scores of supporters, who cheered him on and chanted: "Sabbahi is the symbol of freedom!"
They carried boxes containing the signed forms to be delivered to the electoral committee.
A longtime opposition figure jailed during the rule of strongman Hosni Mubarak and his predecessor Anwar Sadat, Mr Sabbahi came in third in Egypt's first free presidential election in 2012, a year after Mubarak was toppled by an Arab Spring-inspired uprising.
Controversial lawyer Mortada Mansour also announced he was withdrawing from the presidential race and would support Sisi's candidacy.
Mansour is known as a harsh critic of the activists who led the 2011 revolt against Mubarak.
The former judge, who heads Cairo's Zamalek football club, said his decision came in answer to the club members' will and after a "vision" in which he saw himself sitting in a bus with two military officers who told him: "We are going to the new Egypt."
Gen Sisi officially submitted his bid for the presidency on Monday, with his lawyer handing over the required documents. His campaign team said they submitted around 200,000 signatures to the electoral committee.
Critics of Gen Sisi fear his election would mark a return to the autocratic rule of the Mubarak era, citing the military-installed authorities' crackdown on Mursi's supporters and the jailing of prominent activists from the 2011 uprising for organising unauthorised protests.
Gen Sisi has dismissed such fears, and his supporters view him as a strong leader who can stabilise the economically-battered country after three years of turmoil.
The electoral commission is to announce the final field of candidates on May 2, and official campaigning starts a day later.