Egypt's presidential candidates ended their bids for election on Monday as the world's most populous Arab country prepares to head to the polls.
According to electoral rules laid down by the Supreme Presidential Election Commission, the dozen candidates cannot give any media interviews or make public appearances until polls close on Thursday.
The election, which will take two days, is being hailed as a landmark following the February 2011 ouster of long-time president Hosni Mubarak.
The front-runners are former foreign minister and Arab League chief Amr Mussa, Mubarak's last premier Ahmed Shafiq, and the Muslim Brotherhood's Mohammed Mursi and independent Islamist Abdel Moneim Abul Fotouh.
A run-off will be held on June 16-17 if no candidate secures enough votes for victory.
Some 50 million eligible voters are being called to cast their ballots, as a massive security plan is under way.
Interior Minister Mohammed Ibrahim said security forces would deploy at polling stations around the country, particularly at the 351 centres where ballot papers will be taken for the count.
Just moments before the deadline for the "campaign silence," the powerful Muslim Brotherhood's candidate Mursi warned on Sunday against any attempt to tamper with the presidential poll, at a rally attended by thousands of supporters.
Sketchy opinion polls taken by a government-funded think-tank and the cabinet's research division show Mursi trailing behind Abul Fotouh, Mussa and Shafiq.
Some observers have suggested Mursi's final campaign pronouncements may signal that the powerful Muslim Brotherhood, which is presently the largest parliamentary faction, may contest the elections no matter what if he loses.
The Brotherhood, backed by the ultra-conservative Salafi al-Nour party, controls Egypt’s parliament.
The Supreme Council of the Armed Forces - which took charge of Egypt as an interim junta after Mubarak's ouster - pledged a fair election, and has promised to hand power to civilian rule once a new leader is elected.
The military, headed by Mubarak's longtime defense minister Field Marshal Hussein Tantawi, said it was committed to leading the country towards democratization, touting its ability to maintain a relative stability compared with other "Arab Spring" countries like Syria or Libya.
The power transfer will seal the end of a turbulent transition period marked by violent and sometimes deadly protests and a deteriorating economy. It will also mean a key requirement for the release of billions of dollars in US aid to Egypt is met.