An Al-Qaeda source on Monday confirmed the death of one of the leaders of the organisation's north African wing, in the most significant success yet for the French-led operation against Islamist fighters in Mali.
But there were no public celebrations in Paris as relatives of hostages held in the region voiced fear the development leaves their loved ones at greater risk and called for a pause in the bombing to allow for negotiations aimed at securing their release.
Abdelhamid Abou Zeid, a senior figure in Al-Qaeda in the Islamic Maghreb (AQIM), chief was killed last week in a French bombing raid in the Ifogha mountains, an AQIM militant told the private Mauritanian news agency Sahara Medias.
The source insisted however that another Islamist leader, Mokhtar Belmokhtar, was alive and still fighting.
That contradicted claims over the weekend from Chad that its troops had killed the mastermind of the January assault on an Algerian gas plant in January that left 37 hostages dead.
The acknowledgement of Abou Zeid's death came as France's top military official claimed that the intervention launched in January was breaking the back of AQIM and its allies in Mali.
It also coincided with a call by relatives of four of the French hostages held in the region for a pause in the bombing to allow for negotiations with the rebels on the possible release of their loved ones.
Fears the hostages may have been used as human shields or could be subject to reprisal executions have intensified in recent days as the reports on Abou Zeid and Belmokhtar emerged from Chad.
Abou Zeid was believed to have been holding four French citizens kidnapped in Niger in 2010, but the French army's chief of staff, Admiral Edouard Guillaud said that could not be confirmed.
"We do not know where the hostages are," Guillaud said. "We think the hostages are not there (where air strikes are taking place), otherwise we would not be carrying them out."
The hostages' families have repeatedly expressed concern about the possible consequences of France's military intervention in its former colony but Monday's statement was the first time they have publicly challenged the government's approach.
"Today we consider that military operations and the use of force will not result in the hostages being saved," said Rene Robert, the grandfather of Pierre Legrand, one of the four French nationals seized in Niger.
"It is not up to France to raise the white flag, but it is up to France to send signals that will allow the other side to raise a white flag."
Legrand's mother, Pascale Robert, urged Hollande to "declare a pause in the conflict to allow for talks with the remaining figures, rather than fighting on blindly."
French officials avoided responding directly to the hostage families' critique of the current strategy but a foreign ministry spokesman said everything possible was being done to secure the freedom of their relatives.
"The president and the foreign minister have stressed several times our determination (to free the hostages) and the need to work discreetly," he said.
Although the hostage issue continues to cast a cloud over the campaign, French defence officials are happy with its progress.
Guillaud told reporters in Paris that good progress had been made in dismantling what he described as "an industrial terrorist organisation," with French forces having seized more than 50 weapons caches, a dozen workshops and 20 improvised explosive devices.
"It shows that this goes beyond... Mali, beyond even the Sahel, it was expansionist," he said.
"We have cleaned out one of the valleys, a main valley where Chadian and French forces moved in about 10 days ago," he said. "We searched all night and from today (Monday) we will move into the other valleys.
"We are breaking the back of Al-Qaeda in the Islamic Maghreb, that was the goal set by the president," he said.
British Foreign Secretary William Hague meanwhile paid a visit to Mali designed to underline London's backing for the French-led operation.
"My visit, the first by a British Foreign Secretary, underlines the UK's strong commitment to work with international partners to support Mali and countries in the region on countering terrorism and restoring security in the country," Hague said on his arrival in the capital Bamako.
Britain has ruled out sending combat troops to join its ally in Mali but has provided logistical support, notably a Royal Air Force C-17 cargo aircraft, and is due to deploy 40 personnel as part of an EU training mission in Mali.