The body overseeing Egypt's presidential election said it would not announce the results on Thursday as planned, saying it needed more time to study appeals from the candidates, but did not say when it might be ready, Al Arabiya quoted the state news agency as reporting.
The Egyptian presidential run-off pitted the Muslim Brotherhood's Mohamed Mursi against Ahmed Shafik, a former air force commander who was Hosni Mubarak's last prime minister. Both claim to have won and have filed appeals against each other.
"The (election) committee has decided to continue to examine the appeals, which involves looking at records and logs related to the electoral process, and this will necessitate more time before announcing the final results," it said in a statement on Wednesday.
Earlier, Committee Secretary-General Hatem Bagato told Reuters he could not say when the results would be announced.
"We are at the stage of listening to the representatives," he said.
"The committee will meet afterwards to decide on whether to accept the appeals or not. After that, there will be a time set to announce the final result," he added, speaking by phone.
On Tuesday, a U.S. election monitoring group said it was unable to say if Egypt's presidential election was free and fair as it had not been given sufficient access, accusing the military leadership of hampering a transition to democracy.
Beyond the election itself, the group - the Carter Center - said a court's decision to dissolve the Islamist-dominated parliament and a decree from the ruling military council limiting the future president's powers increased the risk that Egypt was not becoming the democracy that many had hoped for.
Omar Salama, a legal advisor and member of the election committee's secretariat, said Morsy had filed over 150 complaints against his rival Shafik. Al Ahram newspaper said on its website that Shafik had submitted 221 complaints about the results.
No official figures have been announced, but candidates had representatives at polling stations and were able to make their own tallies.
"We must give both sides all the time they need to ensure that the process is fair and prevent any claims later on that not enough time was given to both sides," Bagato explained.
If Mursi wins
Should Mursi win, it will be a real test for the Brotherhood's ability to deal with problems on the ground.
The Brotherhood appeared set on a confrontation path with the ruling Supreme Council of the Armed Forces (SCAF) which issued a new constitutional declaration granting itself sweeping powers.
The new dynamics will mean that "SCAF will command the national security of Egypt and leave domestic issues to the president. Any problems and the blame will be shifted to the elected representative," Joshua Stacher, a political analyst and Egypt expert at Kent State University, told AFP.
The SCAF's document said it would retake legislative powers from the Islamist-dominated parliament after the country's constitutional court ordered, last week, the body dissolved.
And it grants the military council veto power over the drafting of a permanent constitution, angering activists who denounced the declaration and an earlier order giving the army power to arrest civilians, as a "coup."
The Brotherhood insists the parliament retains legislative power and has pledged to counter the SCAF decisions with "popular activities."
On Tuesday night, the Brotherhood joined a mass demonstration in Cairo's Tahrir square, which attracted over 15,000 protesters, some celebrating Morsi's win as much as denouncing the military move.