Thousands of protesters gathered at Cairo's historic Tahrir square for a sit-in protest as the presidential election results were delayed by the ruling military council.
The election results were supposed to have been announced on Thursday however the election commission postponed it to Sunday. The council said they need more time to look into the malpractice allegations involved in the voting.
The protesters accused the ruling Supreme Council of the Armed Forces (Scaf) of trying to rig the election results.
"They are trying to steal the election. We will stay here until Mohamed Mursi is declared our President," the Sky News reported the protesters at Tahrir square as saying.
Brotherhood held a meeting among its senior leaders on Thursday after the election commission's announcement of the delay in the results.
Tension mounted in the city of Cairo as scores of demonstrators who came from all corners of Egypt camped in the capital.
However, there were no instances of violence reported from the region.
After the presidential polling took place on Sunday, both Muslim Brotherhood's Mohammad Mursi and former Egyptian dictator Mubarak's Prime Minister Ahmed Shafiq claimed victory in the elections.
The protesters also demanded the council to roll back its sweeping powers which were announced by Scaf, hours after the polling. The hard-won democratic rights of the people would be at great peril, if the military continues to rule in the same way, said the protesters.
Meanwhile Mubarak's ex-aide Shafiq was confident of his victory and accused the Brotherhood of manipulation.
"These protests in the squares, the campaigns of terror and the media manipulation are all attempts to force the election committee to announce a particular result. I am fully confident that I will be the legitimate winner," Shafiq said in a television address.
Scaf which took control of Egypt after the uprising in January ousted Hosni Mubarak, vowed to hand over the country to the elected party by 1 July.
However, Muslim Brotherhood has been accusing the military of trying to rule the nation through a proxy.
SCAF dissolved the parliament days before the elections and left the limitation of president's powers in hanging. This had also angered the Brotherhood.