France provided technical and logistical support to a recent Mauritanian military operation against al-Qaeda's North African wing, the French defence ministry has said.

"The terrorist group targeted by the Mauritanian army is the one that executed a British hostage a year ago and has refused to give proof of life or engage in negotiations to release our compatriot Michel Germaneau," the ministry said on Friday.

"(We) confirm that the French army gave technical and logistical support to a Mauritanian operation to prevent an attack by AQIM against Mauritania," the ministry statement said, using the acronym for al-Qaeda's North African section.

Mauritanian officials said that troops attacked an al-Qaeda-linked group in the border region of northern Mali and Mauritania to free an elderly French hostage facing execution but did not find him.

The raid was held "in co-ordination with friendly countries," the source said, adding that the 78-year-old hostage, Michel Germaneau, an aid worker kidnapped on April 19, was not found.

Spain's El Pais daily quoted diplomatic sources as saying that French special forces had participated in the dawn attack after locating the base with US help.

Al-Qaeda in the Islamic Maghreb (AQIM) set a July 27 deadline for killing Germaneau, unless its demands for a prisoner swap were met.

AQIM gave France 15 days from July 12 to arrange an exchange and said French President Nicolas Sarkozy would be responsible for the life of Germaneau, a retired engineer who had worked in the Algerian oil sector.