French-backed Mauritanian military operations against al Qaeda fighters in the Sahara desert wound up on Saturday after four days of hunting Islamists deep inside Mali, security sources said.
Mauritanian forces, supported by French special forces and intelligence, killed six fighters from al Qaeda's North Africa wing in an attack on a base in Mali on Thursday, marking an escalation in African and European responses to the region's Islamist threat.
"The operation organized by the Mauritanian army against al Qaeda has just finished. The troops involved are on their way back after 4 days of operations," one security source said.
Another security source said that operations had continued some 200 km (124 miles) into Mali after Thursday's pre-dawn attack on a group of Islamists who are believed to be holding a 78-year-old French hostage in the desert Sahel region.
The second source gave no details of any progress, but France said on Friday that it had no information on the fate of Michel Germaneau, a retired engineer who was kidnapped on April 22 and is in the hands of al Qaeda's North African wing, AQIM.
The operation follows mounting calls for better regional and international cooperation in the fight against AQIM, which was previously focused on Algeria but now has two factions that are increasingly active in the remote desert regions of Mauritania, Mali and Niger.
Paris said on Friday it gave technical and logistical support to Mauritanian forces in an operation aimed at preventing an attack by AQIM on Mauritania.
But analysts said it could have been a failed bid to rescue Germaneau, who was kidnapped in Niger and is believed to be in the hands Abdelhamid Abou Zeid, leader of the more hardline of the two AQIM factions operating in the Sahara.
The operation appeared to anger official Mali, which was not involved, and Spain, which also has hostages held by another al Qaeda faction in the region.
AQIM had set France a deadline of next week to agree to a prisoner swap, saying it would otherwise kill Germaneau.
Islamists in the Sahara have so far not staged any large-scale attacks, and analysts say they have concentrated largely on collecting revenues from ransom payments and the smuggling of goods, including cocaine.