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.
Al-Qaeda in the Islamic Maghreb (AQIM) chief Abdelhamid Abou Zeid was killed as a result of a French bombing raid in the Ifoghas 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 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 now breaking the back of the organisation 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 on Monday urged President Francois Hollande to seek talks with AQIM aimed at securing their relatives' release.
"France must give AQIM clear signals of a willingness to negotiate, in liaison with (the hostages' employers) Areva and Vinci," said a statement issued on their behalf.
The 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.
"We want a strong signal to be sent to AQIM to demonstrate a willingness to negotiate," he told AFP.
"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.
"Given the pressure that has been put on them and the difficulties they are facing, perhaps now they will be more willing to negotiate.
"After the military operations, there is now a need for a pause to allow for an opening of dialogue."
As British Foreign Secretary William Hague arrived in Mali's capital, Bamako, for a visit aimed at expressing support for the French-led operation, Admiral Guillaud was delivering an upbeat assessment of 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.