The National Alliance to Support Legitimacy issued a statement on Monday saying that a huge number of Egyptians have boycotted the first day of the presidential elections in protest at the "military takeover."
The Islamist alliance, which supports ousted president Mohamed Morsi, had earlier called for protests during the two polling days, Monday and Tuesday. Protests, were slow to materialise on Monday, but reports of turnout were mixed.
"The Egyptian youth who led the 25 January revolution have showed the world by their boycott of the elections that Egypt has a legitimate president (Morsi)," the statement read.
The Muslim Brotherhood-led coalition insists Morsi is Egypt's legitimate president. The group describes Morsi – who is in prison facing charges including murder and espionage – as the "kidnapped president".
Last week, the alliance declared that votes cast by Egyptians overseas were void, and stressed what they described as a low turnout at polling stations abroad.
A total of 318,033 votes were cast by expats, with El-Sisi winning 94.5 percent of the vote.