|Mohamed ElBaradei, the former chief of the IAEA, had previously expressed interest in running for president [EPA]
Mohamed ElBaradei, the former head of the UN nuclear watchdog and Nobel laureate, has said he will not run for the Egyptian presidency.
Declaring there is still no real political change in the country, ElBaradei said on Saturday in a statement: "My conscience does not allow me to run for the presidency or any other official position unless there is real democracy."
He praised the revolutionary youths who led massive popular uprisings that toppled president Hosni Mubarak last year but said "the former regime did not fall".
ElBaradei compared the revolution to a boat and charged that "the captains of the vessel ... are still treading old waters, as if the revolution did not take place".
He said corruption was still rife in post-Mubarak Egypt, which has been ruled by a military council since the veteran president was removed from power in February following an 18-day popular revolt.
"We all feel that the former regime did not fall," ElBaradei said in the statement.
He denounced the "repressive" policies of Egypt's new rulers, whom he said were putting "revolutionaries on trial in military court instead of protecting them and punishing those who killed their friends".
"The bottom line is that he feels this is not a transition to democracy ... so he wants no part in the process," Al Jazeera's Sherine Tadros said, reporting from Cairo.
"This is a blow to the liberal movement as a whole, just after Islamists swept the vote [for the lower house of parliament]. What they've lost is someone who has a vision and a plan for Egypt's future."
ElBaradei 's comments reflect growing disenchantment with the ruling Supreme Council of the Armed Forces (SCAF).
The SCAF has repeatedly pledged to cede full powers to civilian rule when a president is elected by the end of June, but there is widespread belief that the military wants to maintain a political role in the country's future.
The council has also come under fire over its human rights record in recent months, in the face of accusations that it has been resorting to Mubarak-era tactics to stifle dissent.
Egypt witnessed deadly clashes between democracy protesters and security forces in November - before parliamentary polls began - and again in December.
Mubarak is on trial and the prosecution has called for him to be hanged over the killing of hundreds of demonstrators in the January to February 2011 unrest.