Mali Tuaregs seize two fleeing Islamist leaders By Cheikh Diouara and John Irish KIDAL, Mali/PARIS (Reuters) - Tuareg rebels in northern Mali said on Monday they had captured two senior Islamist insurgents fleeing French air strikes toward the Algerian border and France pressed ahead with its bombing campaign against al Qaeda's Saharan desert camps. Pro-autonomy Tuareg MNLA rebels said one of their patrols seized Mohamed Moussa Ag Mohamed, an Islamist leader who imposed harsh sharia (Islamic law) in the desert town of Timbuktu, and Oumeini Ould Baba Akhmed, thought to be responsible for the kidnapping of a French hostage by al Qaeda splinter group MUJWA. France has deployed nearly 4,000 ground troops, as well as warplanes and armored vehicles in its three-week-old Operation Serval that has broken the Islamist militants' 10-month grip on northern towns. It is now due to gradually hand over to a U.N.-backed African force of some 8,000 troops, known as AFISMA, of which around 3,800 have already been deployed. After meeting French President Francois Hollande in Paris, U.S. Vice President Joe Biden praised the "decisiveness and incredible competence" of France's operations. He backed France's call for U.N. peacekeepers to be deployed in Mali. "We agreed on the need to, as quickly as reasonably possible, establish an African-led mission to Mali and, as quickly as is prudent, transition that mission to the United Nations," Biden said, flanked by Hollande. Paris believes that deploying U.N. peacekeepers to Mali could eliminate problems over funding the African mission and fears of ethnic reprisals by Malian troops against light-skinned Tuaregs and Arabs associated with the Islamists. The MNLA, which seized control of northern Mali last year only to be pushed aside by better-armed Islamist groups, regained control of its northern stronghold of Kidal last week when Islamist fighters fled French air strikes into hideouts in the nearby desert and rugged Adrar des Ifoghas mountains. "One of the first conditions for reconciliation is to disarm rebel groups," Malian Foreign Minister Tieman Hubert Coulibaly told Reuters in Paris. We must first liberate the north of Mali and then we can organize elections. The French presence at the airport has since been reinforced by two parachute units. Though the MNLA says it controls Kidal, France's defense ministry said on Monday that 1,800 Chadian troops - part of a U.N.-backed African mission sent to help retake northern Mali - had entered the city. "The objective is to destroy their support bases, their depots because they have taken refuge in the north and northeast of the country and can only stay there in the long-term if they have the means to sustain themselves," Fabius said. Jets attacked rebel camps on Sunday targeting logistics bases and training camps used by the al Qaeda-linked rebels near Tessalit, a town close to the Algerian border. In all, French jets and attack helicopters have hit 25 targets in Kidal and areas surrounding Aguelhok and Tessalit since Friday, the defense ministry said. Hollande made a one-day trip to Mali on Saturday, promising to keep troops in the country until the job of restoring government control in the Sahel state was finished. The rebels' retreat to hideouts in the remote Adrar des Ifoghas mountains - where Paris believes they are holding seven French hostages - heralds a potentially more complicated new phase of France's intervention in its former colony as special forces teams try to track the rebels to their hideouts. Shehu Abdulkadir, the Nigerian commander of AFISMA, said the African force was preparing a strategy to free the hostages, but he declined to provide any details. Hollande said on Saturday that Paris would withdraw its troops from Mali once the landlocked West African nation had restored sovereignty over its territory and AFISMA was ready to take over most military operations on the ground. The deployment of the African force, however, has been badly hampered by shortages of kit and airlift capacity and questions about who will fund the estimated $1 billion cost. Fabius said French soldiers could soon pull back from Timbuktu. Residents of the ancient caravan town had feted Hollande on Saturday in thanks for their liberation from Islamists, who had handed down punishments including whipping and amputation for breaking sharia. Additional reporting by John Irish and Vicky Buffery in Paris, Daniel Flynn in Dakar and David Lewis in Timbuktu; Writing by Daniel Flynn; Editing by Pascal Fletcher and Mark Heinrich