(CNN) -- Omar Suleiman, whom former President Hosni Mubarak had appointed vice president shortly before his exit, announced Friday that he plans to enter the race to become Egypt's next president.
The former head of Egyptian intelligence recently said he did not plan to seek the presidency in the first election for the post since the revolution that led to Mubarak's exit.
But on Friday, as his supporters took to the streets urging him to run, Suleiman did an about-face and said he will now "participate in the nominations, regardless of my previous statement about the difficulties and challenges."
"I promise you, my brothers and sisters, to complete the goals of the revolution and provide security and stability to the Egyptian people," he said in a written statement.
Thousands of his backers gathered Friday in Cairo's Abbasiya Square, where unknown assailants drove by and fired into the crowd, his campaign said. Shortly after reporting the attack, the state-run MENA news agency said 15 people were "injured in clashes between Suleiman supporters (and) thugs."
Suleiman is no stranger to the Egyptian government, and has been closely tied to Mubarak -- the man whose resignation, under intense pressure, spurred the political upheaval that led to, among other things, this election. Leading opposition figure Mohamed ElBaradei has said that Suleiman and Mubarak are "twins."
"His loyalty to Mubarak seems rock solid," a former U.S. ambassador wrote in 2007 in a classified U.S. diplomatic cable leaked to the website WikiLeaks.
And he could become Egypt's first president since Mubarak -- assuming he can collect 30,000 valid signatures by this weekend and beat out what is already a crowded field of candidates.
More than 450 people have entered the race -- including Muslim Brotherhood candidate Khairat al-Shater; former Egyptian Foreign Minister and Arab League Secretary-General Amre Moussa; and Ayman Nour, an opposition leader jailed by Mubarak who was recently pardoned.
The official three-week campaigning period starts April 30. No candidate can spend more than 10 million Egyptian pounds ($1.65 million) ahead of the election, which starts May 23.
Suleiman is well-respected by the military, whose leaders have ostensibly ruled Egypt during these months of political transition, and has been credited with crushing an Islamic insurgency in the 1990s. Last year, then-U.S. State Department spokesman P.J. Crowley said Suleiman "is someone that we know well and have worked closely with."
Mubarak named him Egypt's vice president in late January 2011, the first time anyone had held such a position since Mubarak came to power in 1981.
Less than two weeks later, Suleiman said that Mubarak had resigned and the Supreme Council of the Armed Forces would "run the affairs of the country" -- ending his extensive government career, at least for the time being.
Born in an impoverished area of southern Egypt in 1935, Suleiman chose the military as a career and rose to the rank of lieutenant general, according to a Foreign Policy magazine biography. He trained in both the United States and the Soviet Union during the Cold War.
He became head of the Egyptian General Intelligence Organization in 1993, at a time when the Arab world's most populous nation was wracked by terrorist attacks targeting tourists and essential infrastructure. Defense and security analysis company IHS Jane's said that Suleiman's ascension was helped by his interactions with the Israeli Mossad as well as the U.S. Central Intelligence Agency.
Author Ron Suskind, whose 2006 book "The One Percent Doctrine" focused on the post-9/11 counterterrorism policies of U.S. President George W. Bush's administration, said that Suleiman wielded significant power, and flexed his muscles, behind the scenes.
"If someone knocks on your door and you disappear, Omar Suleiman is probably behind it," Suskind told CNN last year. "He is a feared man, and certainly not a man with any legitimacy when it comes to rule of law or any of the principles we prize in America."
Alaa Awad, a senior member of the Muslim Brotherhood, said it is conceivable that Suleiman "was taking orders from Mubarak and ... that his experience as an intelligence official may come in handy by uplifting Egypt's security."
But he added that "any revolutionary logic cannot accept that a vice president appointed by Mubarak becomes the nation's next president."
"The fact remains that he was from Mubarak's inner circle, so it's not acceptable under any circumstances," Awad said.
Journalist Mohamed Fadel Fahmy contributed to this report.