Egypt's Islamist leader Mohamed Morsi must "hear" popular demands, French Foreign Minister Laurent Fabius said Tuesday, after the defiant president snubbed an ultimatum to step down.

"When there is such a mass of problems and such a mass of people expressing what is not than just unease but censure and distress, the Egyptian government must listen to the people... President Morsi must hear what is taking place," he said on the i-Tele network.

"France wants a dialogue," he said. "The economic situation has worsened a lot and that explains the 15 million people" in the streets.

A longtime leader of the long banned Muslim Brotherhood, Morsi was elected last year in the aftermath of the 2011 uprising that ended three decades of authoritarian rule by Hosni Mubarak.

His opponents accuse him of having betrayed the revolution by concentrating power in Islamist hands and of sending the economy into freefall.

His supporters say he inherited many problems from a corrupt regime, and that he should be allowed to complete his term, which runs until 2016.