Former Egyptian president Hosny Mubarak, who was serving a life sentence in a prison hospital, was clinically dead after being transferred to a military hospital in Cairo, security sources told dpa.
Mubarak suffered a stroke Tuesday and was moved to a military medical facility.
Egyptian state media said he suffered a stroke, after earlier reports that doctors used a defibrillator to restart Mubarak's heart after it stopped for a few seconds.
Mubarak's health has been deteriorating since his arrival last June in the Tora prison hospital, south of Cairo, after a court sentenced him to life in prison on charges related to the deaths of protesters.
Tight security was imposed around the military hospital in Maadi district, where Mubarak was transferred, and journalists were banned from entering the facility, according to Al-Ahram newspaper.
Mubarak ruled for three decades before being ousted in February 2011 following a popular uprising. The Supreme Council of the Armed Forces took control of the country after Mubarak was forced to step down.
His death comes after the weekend's presidential elections, seen as Egypt's first free polls ever.
Activists and opposition figures have charged that the ruling junta gave Mubarak special treatment since his ouster.