(CNSNews.com) – Egypt’s historic presidential election campaign, already thrown into disarray by the Muslim Brotherhood’s decision to breach earlier pledges not to field a candidate, is now being roiled by calls for another leading Islamist contender to withdraw over his mother’s U.S. citizenship.

If Sheikh Hazem Abu Ismail, a candidate popular among hardline Salafis, is forced to pull out, the chances of the Muslim Brotherhood’s newly-announced presidential hopeful, Khairat el- Shater, winning the election will be further strengthened.

Egypt’s election commission confirmed on Thursday that Ismail’s late mother had held American citizenship – Ismail himself has repeatedly denied it – but stopped short of declaring him disqualified. It plans to vet candidates’ eligibility once the filing of applications to run closes on Sunday.

Egyptian law requires presidential candidates, their parents and spouses to be Egyptian citizens and to have never held any other citizenship.

Meanwhile a third candidate, former spy chief Omar Suleiman – who served briefly as vice president during the closing days of Hosni Mubarak’s regime – left the race on Wednesday, further narrowing voters’ options in the May election.

Ismail, who has run a high-profile campaign, pledged to implement shari’a in Egypt and to annul the three decade-old peace treaty with Israel. He has also been a strong critic of the ruling military council.

The independent Al-Masry al-Youm newspaper quoted some Ismail supporters as alleging a conspiracy involving the Egyptian military and U.S. government to produce fake U.S. citizenship papers as so force his disqualification.

The candidate himself fanned the flames, saying in a statement on his Facebook site, “There has been a well-orchestrated plan in play for a long time. Many bodies used forces inside and outside the country to subdue my presidential campaign,” according to the paper.

Alleging a political and media campaign against their favored candidate, Salafists said they plan to protest in Cairo’s Tahrir Square in support of Ismail on Friday.

An opinion poll by the Al-Ahram Centre for Political and Strategic Studies last month – before the Brotherhood’s al-Shater joined the contest – found 22.7 percent support for Ismail and 9.3 percent support for Suleiman, so their departure could see a full one-third of potential votes redistributed.

The frontrunner in that poll was former foreign minister and Arab League Secretary-General Amr Moussa, with 31.5 percent.

Two Islamist parties, the veteran Muslim Brotherhood and the smaller Salafist Nour party, together dominate post-Mubarak Egypt’s political institutions after recent elections. The Brotherhood controls the largest number of seats in both chambers of parliament and in an assembly that is drawing up Egypt’s new constitution.

Apart from al-Shater, Moussa and the possibly departing Ismail, other presidential candidates include yet another Islamist, Abdel Moneim Abouel Fotouh – who left the Muslim Brotherhood when he joined the race, since the Brotherhood at that time said it was not participating. He scored 8.3 percent in the Al-Ahram poll.

Also running is Ahmed Shafiq, who served briefly as Mubarak’s prime minister during the upheavals early last year (10.2 percent in the Al- Ahram poll); Hamdeen Sabahi, leader of a Nasserite party (five percent in the poll); and Salim al-Awa, an Islamist scholar (four percent in the poll).

The list of candidates is likely to change further before Sunday’s deadline for submissions. The final list of eligible candidates will be announced later this month.

Elections are scheduled for May 23 and 24. Should no candidate receive 50 percent of the votes a second-round runoff between the two top-scoring aspirants will be held in June. Egypt’s military council has pledged to hand over power to an elected president by the end of June. (copyright 1998-2012 Cybercast News Service 04/06/12)