A French defense ministry source says its forces in West Africa found no trace of kidnap victim Michel Germaneau during a military operation against an al-Qaida group believed to be holding him.
The source told reporters Saturday 20 to 30 French intelligence and special forces joined Mauritanian troops in the raid in Mali on Thursday. The Defense Ministry had earlier confirmed France provided "technical and logistical" assistance.
Six militants from al-Qaida in the Islamic Maghreb were killed in the encounter.
But there were conflicting reports Saturday whether France was continuing operations to rescue the 78-year-old Frenchman.
According to some reports, French security sources said operations were under way in Mali, while others reported the attempts had been suspended.
Al-Qaida in the Islamic Maghreb has given France until Monday to arrange a prisoner exchange for Germaneau's release. The group has threatened to kill him if Paris does not meet the deadline.
The terrorist group operates across a vast desert region that includes Algeria, Mali, Niger, and Mauritania.
The group killed British captive Edwin Dyer last year after London refused to yield to its demands.
It is also holding two Spanish aid workers kidnapped in November.
Germaneau and his Algerian driver were kidnapped in the desert region near Niger's border with Algeria and Mali in April. The driver was released later that month.
Some information for this report was provided by AFP and Reuters.