By Richard Valdmanis and David Lewis
MARKALA, Mali/DAKAR (Reuters) - A split emerged on Thursday in the alliance of Islamist militant groups occupying northern Mali, as French and African troops prepared an offensive aimed at driving them from their safe haven in the Sahara.
A senior negotiator from the Ansar Dine rebels who helped seize the north from Mali's government last year said he was now part of a faction that wanted talks and rejected the group's alliance with al Qaeda's North African franchise AQIM.
It was unclear how many fighters had joined the new Islamic Movement of Azawad (MIA) faction. But the announcement will encourage international negotiators who have long sought to prise apart the Islamist alliance, seen as a major threat by Washington and other Western and regional powers.
"There has to be a ceasefire so there can be talks," Alghabass Ag Intallah, an ethnic Tuareg, told Reuters from the Ansar Dine stronghold of Kidal in northeast Mali. The new MIA would focus its efforts on seeking autonomy for the northern homeland of the desert Tuaregs, he said.
For nearly two weeks, French aircraft have bombarded rebel positions, vehicles and stores in the center and north of Mali as a ground force of African troops assembles to launch a U.N.-backed military intervention.
The strikes halted a rebel advance further south. French and Malian ground troops have also retaken several towns after the insurgents avoided a head-on fight, abandoning vehicles and slipping away into the scrubland.
On Thursday, a Reuters correspondent saw around 160 troops from Burkina Faso deployed in the dusty central Malian town of Markala - the first West African troops to link up with French and Malian forces. They replaced French soldiers protecting a bridge over the Niger River.
Malian women pounding millet by the roadside stopped to wave as French armored vehicles, trucks and jeeps rumbled north from Segou - some 30 km (20 miles) from Markala - heading for the town of Diabaly, recently recaptured from the rebels.
REPORTS OF REPRISAL KILLINGS
News of the French and African advances has been overshadowed by allegations from residents and rights groups that Malian government soldiers have executed Tuaregs and Arabs accused of collaborating with the rebels.
Mali's army has denied the allegations but the reports of killings of lighter-skinned Tuaregs and Arabs by Mali's mostly black army has raised the risk that the internationally-backed intervention could trigger an ethnic bloodbath.
"These people took up arms against us, our colleagues were killed ... I no longer have any Tuareg friends," one Malian soldier, who asked not to be named, told Reuters.
Outside Diabaly, a town of mud-brick huts amid mango trees surrounded by irrigation canals 350 km (220 miles) north of the capital Bamako, Malian army soldiers captured a group of suspected Islamists found hiding in a local house, said a Malian officer, Captain Samasa, who only gave his first name.
The captives were taken away in a truck, witnesses said.
Mali's top Muslim leader accused foreign Islamists in the north of trying to impose an alien version of Islam on a country that had been Muslim for a millennium.
"What right do they have to impose the sharia (Islamic law) here?" Imam Mahmoud Dicko, head of the High Islamic Council in Bamako, asked in an interview in the French Catholic daily La Croix.
The rebels have destroyed historic Muslim shrines, which they considered heretical, and imposed harsh punishments that they say sharia demands such as stoning adulterers to death and chopping off thieves' hands.
CALL FOR U.N. PEACEKEEPERS
The Islamist alliance in the north holds the major towns of Timbuktu, Gao and Kidal. It groups AQIM, Ansar Dine and AQIM splinter MUJWA, and the numbers of its fighters are estimated at roughly 3,000.
Fears that it could pose a threat to African neighbors and Western powers increased sharply last week when al Qaeda-linked guerrillas opposing the French-led military intervention in Mali briefly seized a gas plant in neighboring Algeria. At least 37 foreign hostages were killed in the incident which ended when Algerian forces stormed the facility.
Reflecting the wider security worries, France has ordered special forces to protect uranium sites run by French company Areva in Mali's neighbor Niger, which supplies fuel for the French nuclear power industry.
There are concerns too that the intervention in Mali could force the Islamist rebels across desert borders, destabilizing neighbors. A Libyan minister said U.N. peacekeepers should be deployed after the initial offensive.
Military experts say a fast deployment of the African ground force, expected to eventually number more than 5,000, is essential to sustain the momentum of the French operations in Mali. The operation will be high on the agenda of an African Union summit in Ethiopia's capital Addis Ababa this weekend.
Most of the African troops for the Mali intervention are coming from member countries of the West African regional grouping ECOWAS, such as Benin, Nigeria, Senegal, Togo and Niger.
The deployment also includes soldiers from Chad who are experienced in desert warfare. Burundi has also offered troops.
But there are questions over whether the African force has the arms, equipment and training needed for a sustained campaign in a desert and mountain battleground the size of Texas.
International donors are due to meet in Addis Ababa on January 29 to discuss the African military operation, and France said they would be asked for about 340 million euros ($452 million.
El-Ghassim Wane, director of the AU's Peace and Security Council, said that besides the West, the AU was also looking for financial and material support from China for the Mali operation. China was already backing an African peacekeeping operation in Somalia, he said.
(Additional reporting by John Irish, Geert de Clercq, Muriel Boselli, Michel Rose and Tom Heneghan in Paris, Aaron Maasho and Richard Lough in Addis Ababa; Writing by Pascal Fletcher and Daniel Flynn; Editing by Andrew Heavens and Robin Pomeroy)