A French corporal was killed tracking down jihadist fighters in their northern Mali mountain bastions, bringing to five the number of French deaths since Paris launched a military offensive in the country two months ago. Defence Minister Jean-Yves Le Drian said Sunday the 24-year-old soldier was killed and three of his comrades wounded when their vehicle was struck by a roadside bomb blast in the Ifoghas mountains, without saying when it happened. Meanwhile, the African Union's Peace and Security Council was chairing an international conference in Nouakchott on the situation in northern Mali and the broader region where Al-Qaeda-linked groups have been prospering. With French special forces and aerial firepower, the French-led offensive took only days to reconquer the main cities in northern Mali, which Al-Qaeda's North African franchise and its allies had controlled since last spring. But the bulk of Islamist fighters moved north to fight from their remote mountain strongholds and France has admitted that flushing them out was the most perilous phase of its involvement. And in a sign the conflict is far from over, five missiles exploded a few kilometres outside the main northern city of Gao overnight, although there were no casualties. The Islamists were driven from Gao on January 26, but the city suffered a series of suicide attacks and other raids last month, which has led residents to fear for the worst when the French leave. President Francois Hollande has already said he planned to scale back French military presence in the former colony as early as next month and start handing over responsibility to Malian troops and an African stabilisation force. The AFISMA force set up by regional west African bloc ECOWAS has been slow to deploy however and it needs funding and training. Residents of Gao, Timbuktu and other cities recaptured by French-led troops in January have voiced fears that Islamist fighters would resurface and sow terror in the region as soon as Paris withdraws its 4,000 soldiers. However, according to a survey by a local charity, some 6,000 people who had fled Gao have recently moved back to their homes. World Food Programme executive director Ertharin Cousin also warned Sunday that the humanitarian crisis in Mali, once one of west Africa's most stable democracies, was far from over. On a visit to Mali, she called for a redoubling of efforts to help the displaced return to their homes, saying there was still work to do. The AU ministerial meeting in the Mauritanian capital, also attended by senior European Union and UN officials, was focused on "facilitating the realisation of AFISMA's mandate". The meeting was also due to look at ways of strengthening security along Mali's long desert borders, which Islamist fighters, drug smugglers and human traffickers have been crossing at leisure. France has said a possible UN peacekeeping force that could number as many as 10,000 troops, could start deploying in June.