France says it has not received any demands from al-Qaida's north African branch for the release of seven hostages, including five French citizens.
Al-Arabiya television reported Monday that the kidnappers are demanding France repeal its ban on face veils in exchange for the hostages' freedom.
But an official at French President Nicolas Sarkozy's office said Tuesday that there has been no message and no request from the group, known as Al-Qaida in the Islamic Maghreb.
France recently approved a law that forbids the wearing of full-face coverings in public, except in places of worship.
Al-Arabiya said the kidnappers also are demanding the release of some prisoners being held in France, and a ransom of $9.7 million.
Gunmen kidnapped the five French nationals, a Togolese and a Madagascan September 16 in northern Niger. Officials have said they believe the hostages are now in neighboring Mali.
Late Sunday, an official in Niger said the sole woman in the group, French national Francoise Larribe, was ill when kidnapped and needs medical attention.
A video of the hostages was posted on the website YouTube on September 30, in which the hostages all name Al-Qaida in the Islamic Maghreb as their abductors.
The captives include two employees of the French nuclear energy firm Areva and five with a subsidiary of the French construction company Vinci.
Al-Qaida in the Islamic Maghreb has carried out previous kidnappings in the region, including that of a 78-year-old Frenchman who was abducted in Niger in April and later killed.
Some information for this report was provided by AP, AFP and Reuters.