East Cairo prosecution has ordered the detention of Salafist preacher Hazem Salah Abu Ismail for four days pending investigations on charges of forging his mother's nationality during Egypt's 2012 presidential elections.

Investigations revealed that Abu Ismail lied in his papers submitted to the presidential elections committee, claiming that his mother had no passport other than the Egyptian one. 

Abu Ismail, a prominent lawyer, was disqualified from the presidential race that brought Mohamed Morsi to power in June 2012 after reports that his mother held a US passport.

During investigations he admitted to have drafted the papers, but he denied knowing that his mother held a US passport.

Under Egypt's election rules, the candidate's parents must be Egyptian and not acquire the citizenship of another country.

He later won a court case against the interior ministry in April 2012 after authorities failed to provide proof that his mother did hold dual nationality.

Abu Ismail, who is known for his close ties with Muslim Brotherhood, was arrested on 5 July for allegedly inciting violence against opponents to the deposed president.