* MNLA say holding senior rebel who enforced sharia in Timbuktu
* French jets pound Islamist camps, bases near Algeria border
* France says army aims to destroy Islamist supply lines
* French forces could soon pull back from Timbuktu
By Cheikh Diouara
KIDAL, Mali, Feb 4 (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 they had seized Mohamed Moussa Ag Mohamed, an Islamist leader who imposed harsh sharia law in the desert town of Timbuktu, and Oumeini Ould Baba Akhmed, believed to be responsible for the kidnapping of a French hostage by the 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 3,500 ground troops, and warplanes and armoured vehicles in its three-week-old Operation Serval (Wildcat) in Mali which has broken the Islamists' 10-month grip on northern towns, where they imposed sharia law.
Paris and its international partners want to prevent the Islamists from using Mali's vast desert north as a base to launch attacks on neighbouring African countries and the West.
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 airstrikes into 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.
French special forces took the airport in Kidal on Tuesday, reaching the most northern city previously held by the Islamist alliance. Though the MNLA says it controls Kidal, a Reuters reporter in the town saw a contingent of Chadian troops - part of a U.N.-backed African mission being deployed to help retake northern Mali - backing up French special forces there.
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 north-east 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, close to the Algerian border.
French President Francois 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 saviour 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.
"We are still in the same war, but we're entering a new battle," said Vincent Desportes, a French former general and now associate professor at Science-Po university in Paris.
"We will look to gradually wear out and destroy the terrorists that are sheltering in the Ifoghas. It's now a war of intelligence (services), strikes and probably action by special forces in the background."
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 a U.N.-backed African military force could take over from the French soldiers.
Drawn mostly from Mali's West African neighbours, this force is expected to number more than 8,000. But its deployment 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 may soon pull back from Timbuktu. Its residents had celebrated their liberation from the Islamists, who had handed down punishments including whipping and amputation for breaking sharia law.
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 in Paris, Daniel Flynn in Dakar and David Lewis in Timbuktu; Writing by Daniel Flynn; Editing by Pascal Fletcher and Jon Boyle)