Egyptian Foreign Minister Mohamed Kamel Amr tendered his resignation on Monday night, the state news agency MENA reported, after millions of Egyptians rallied against President Mohammed Morsi.
The report did not elaborate or cite any sources for the information. At least five other ministers have resigned since Sunday's mass protests.
Meanwhile, Egypt’s Islamist National Alliance has called for mass rallies in support of embattled President Mohammed Morsi, following a 48-hour army ultimatum for all parties to reach a resolution.
Al Arabiya reported that the Muslim Brotherhood and other Islamist groups began amassing their supporters in different provinces on Monday night, with a focus on Cairo and Giza.
Activists reported that a pro-Morsi rally headed toward Cairo University, where Islamists plan to stage an open sit-in to counter opposition rallies.
During its press conference, the National Alliance of Islamist parties, including the Muslim Brotherhood, rejected the use of army to “assault legitimacy” in a way that leads to a coup.
Earlier, the country’s Defense Minister General Abdel Fattah al-Sissi issued a 48-hour ultimatum to all Egyptian political forces to reach a resolution or face a military “road map for the future” that “will not exclude anyone.”
A senior member of the Muslim Brotherhood's Freedom and Justice Party (FJP) later rejected the ultimatum, saying that “the age of military coups is over."
The Islamist Alliance said it respects all initiatives to resolve the crisis but it must be based on the constitution. It also condemned acts of violence that killed a dozen protesters and wounded hundreds others.
Supporters and opponents of Morsi exchanged gunfire in the city of Suez at the mouth of the Suez Canal on Monday, witnesses said, according to Al Arabiya.
At least 16 people have been killed in clashes between rival protesters since Sunday, when millions of Egyptians flooded the streets to demand that Morsi resign.
Meanwhile, Nour, Egypt's second biggest Islamist party, said it feared the army's return to public life "in a big way".
A member of Nour told the website of the Al-Ahram newspaper that the party believed Egypt's national security was threatened by the division between the ruling Islamists and their opponents.
The party released a statement calling for early presidential elections and the formation of a technocratic government, reported Al-Ahram.
The party further demanded the formation of a committee tasked with amending Egypt's post-revolution constitution, albeit without changing articles related to the "state's identity."