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.
"We chased an Islamist convoy close to the frontier and arrested the two men the day before yesterday," Ibrahim Ag Assaleh, spokesman for the MNLA, told Reuters from Ouagadougou in Burkina Faso. "They have been questioned and sent to Kidal."
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.
Paris and its international partners want to prevent the Islamists from using Mali's vast desert north as a base to launch attacks on neighboring African countries and the West.
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.
BAMAKO HESITATES OVER TALKS
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.
The Tuareg group says it is willing to help the French-led mission by hunting down Islamists. It has offered to hold peace talks with the government in a bid to heal wounds between Mali's restive Saharan north and the black African-dominated south.
"Until there is a peace deal, we cannot hold national elections," Ag Assaleh said, referring to interim Malian President Dioncounda Traore's plan to hold polls on July 31.
Many in the southern capital Bamako - including army leaders who blame the MNLA for executing some of their troops at the Saharan town of Aguelhoc last year - strongly reject any talks.
"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."
French special forces took the airport in Kidal on Tuesday, reaching the most northern city previously held by the Islamist alliance. 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.
TARGETING REBEL BASES, DEPOTS
French Foreign Minister Laurent Fabius said warplanes were continuing bombing raids on Islamists in Mali's far north to destroy their supply lines and flush them out of remote areas.
"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.
"The army is working to stop that," he told French radio.
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. He was welcomed as a savior by cheering Malians.
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.
The rebels also smashed sacred Sufi mausoleums and destroyed or stole some 2,000 ancient manuscripts at the South African-sponsored Baba Ahmed Institute, causing international outcry.
"A withdrawal could happen very quickly," Fabius said. "We're working towards it because we have no desire to stay there for the long-term."
(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)