Egypt's election commission is postponing the release of official results that were due today in a presidential election claimed by both candidates, as tension rose over who will succeed ousted president Hosni Mubarak after moves by the ruling military to extend powers, AFP and Bloomberg have reported.

A new date for the release of election results has not been given.

The state-run news agency MENA reports that the election commission decided to delay announcing the outcome because "it needs more time to review appeals based on alleged voting irregularities submitted by Muslim Brotherhood candidate Mohamed Mursi and by Ahmed Shafiq".

The delay complicates the race between the two most divisive candidates, Bloomberg reports, threatening to further stoke the tensions marring Egypt's transition.

The run-off, which took place on June 16 and 17, pitted Muslim Brotherhood candidate Mohamed Mursi against Mubarak's last prime minister Shafiq, whose participation in the polls was protested by thousands of Egyptians.

The announcement of the results postponement came amid uncertainty about Mubarak's health, after a series of conflicting reports claiming that he had either been declared "clinically dead" or was in a coma.