Tunisia's Constitutional Council has announced that under the constitution the speaker of parliament, not the prime minister, is interim president, state television reported.
The council, the country's highest legal authority on constitutional issues, also said the constitution requires new presidential elections to be held no later than 60 days from now, state television reported.
Tunisia's president Zine El Abidine Ben Ali has been officially ousted from power, the country's Constitutional Council decided Saturday in a ruling published by the official news agency TAP.
Meanwhile, Arab League urged Tunisia to reach national consensus to emerge from crisis, respect will of people.
French President Nicolas Sarkozy on Saturday called a ministerial meeting on the Tunisian crisis and the fate of French nationals in the North African country, his office said.
Late Friday Sarkozy had already held talks on Tunisia at the Elysee Palace with Fillon.
France had earlier Friday "taken note" of the change of leadership in Tunisia, where Prime Minister Mohammed Ghannouchi announced that he had taken over as interim head of state after ousted leader Zine El Abidine Ben Ali fled the country with his family.
The foreign ministry formally confirmed Ben Ali had not asked for asylum and a government source said he would not be welcome.
A source close to government thinking told AFP Paris did not want to risk upsetting its large population of Tunisian immigrants and French citizens of Tunisian origin, saying: "There are a million Tunisians in France, most of them anti-Ben Ali."
Early on Saturday, Saudi Arabia announced it had taken in Ben Ali "out of concern for the exceptional circumstances facing the brotherly Tunisian people and in support of the security and stability of their country".
Three witnesses told Reuters by telephone on Saturday that tens of prisoners have been killed in a fire at a jail in the Tunisian resort town of Monastir and other inmates have fled.
"Right now the Monastir prison is on fire. I can see tens of dead and tens of prisoners who have escaped. The whole prison is on fire, the furniture, mattresses, everything," said local man Shokri Chouchan. Two other witnesses gave Reuters similar accounts of the fire.