Hazem Salah Abu-Ismail, the Salafist former presidential candidate, has called on voters to back pro-revolution candidates in Egypt's presidential election to counteract what he claimed were efforts to restore old regime figures to power.

"To all my Egyptian brothers," Abu-Ismail said on his official Facebook page Thursday. "I urge you to vote because I'm concerned at the huge spending and efforts taking place to re-establish the ousted regime…For the sake of God, let us vote for candidates that weren’t part of the former regime so we don’t regret losing the country."

The Salafist has backed Abdel-Moneim Abul-Fotouh, the former Muslim Brother, for president.

Amr Moussa, Mubarak's former foreign minister, and Ahmed Shafiq, Mubarak's last prime minister, are both running for president.

Sheikh Gamal Saber, Abu-Ismail's former campaign manager, is backing the Muslim Brotherhood’s Mohamed Morsi for president, he announced Tuesday.

Morsi is the only candidate who has stated he will implement Islamic law if elected, Saber said.

The Salafist Nour Party and Al-Jamaa Al-Islamiya's Building and Development Party, as well as other ultra-conservative Salafist groups, the Salafist Call and Al-Jamaa Al-Salafiya, are officially endorsing Abul-Fotouh, the moderate Islamist presidential candidate.

Abu-Ismail was eliminated from the presidential race in April by the Supreme Presidential Electoral Commission (SPEC) due to his late mother's dual Egyptian-American nationality.

Elections are taking place on Wednesday and Thursday with a runoff vote on 16 and 17 June if no single candidate wins an outright majority.

The president will be formally named on 21 June.