Egypt's presidential candidate Hazem Abu Ismail is likely to be disqualified after the electoral commission confirmed Saturday that his mother held U.S. citizenship.

The United States has responded to Egypt's Foreign Ministry in two letters, one saying Nawal Abdul-Aziz Nour, mother of Abu Ismail, obtained U.S. nationality on Oct. 25, 2006, and the other with a copy of Nour's application for U.S. citizenship, Egypt's Higher Presidential Election Commission said.

Egyptian Foreign Ministry sent the document to the commission in response to its inquiry about the nationalities of Abu Ismail and other candidates, their spouses and parents.

Under Egyptian law, a presidential candidate, his parents and wives can only have Egyptian nationality. Abu Ismail, a popular Salafist, has submitted his candidacy papers to join the presidential race. Among the top hopefuls are Khairat al-Shater from the Muslim Brotherhood (MB), former prime minister Ahmed Shafiq, former Arab League chief Amr Moussa and former MB member Abdel Moneim Abou Fotouh.

The candidacy registration, which started on March 10, is set to end on Sunday. The election commission will examine their applications and officially announce the final list of candidates on April 26.

The presidential vote, the first after the fall of ex-President Hosni Mubarak in February 2011, will be held on May 23 and 24, with a run-off in June if no one wins in the first round.

The Supreme Council of the Armed Forces (SCAF), which rules during the transitional period, will hand over power by June 30.