* Burkina Faso, Niger, Mauritania "obsessed" about contagion
* Says may be bigger Islamist threat than Iraq, Afghanistan
By Steve Scherer
ROME, March 12 (Reuters) - Mali's neighbours fear Islamist fighters may lead rebellions in their own countries after al Qaeda-linked fighters took over much of the north African country before being beaten back by French forces, a special envoy to the region said on Tuesday.
If fundamentalist Islamic fighters became rooted in the troubled Sahel region, which stretches across all of northern Africa, it could be a bigger threat to the West than Iraq or Afghanistan, Romano Prodi said.
U.N. Secretary General Ban Ki-moon appointed former Italian prime minister and European commission president Prodi special envoy to the Sahel in October. Since then, Prodi has met the leaders of the countries personally.
"Burkina Faso, Niger, and Mauritania all have the same type of shared fear and obsession of contagion. This is understandable because they are countries without borders," Prodi told Reuters.
"Chad is a little different because it has a strong army."
The Sahel is a 1,000-km-wide (600-mile) strip of Saharan desert and savannah that runs the breadth of the continent with few visible borders, and which has been regularly stricken by drought and famine.
"The Western world had no idea what Sahel was because history has taken the attention of NATO and Western countries to Iraq and to Afghanistan, but Sahel is potentially even more dangerous... certainly than Afghanistan," Prodi said, citing the mobility of Islamist fighters and their proximity to Europe.
France launched a ground and air operation on Jan. 11 to break Islamist rebels' hold on the northern two-thirds of Mali, saying the militants posed a risk to the security of West Africa and Europe.
While the rapid offensive has now taken back virtually all of the territory seized by the militants nearly a year ago, French and allied Chadian forces have met heavy resistance from militants holed up in mountains near the Algerian border.
Clashes also are continuing near Gao, northern Mali's biggest town.
"The number and the strength of the terrorists was heavily underestimated," Prodi commented.
GUARANTEES FOR NORTHERN MALI
Prodi said it would be up to the Security Council to decide the U.N.'s future moves in Mali, but he said that an international guarantee for an "equitable distribution of public money" to northern Mali would be necessary.
Mali had been held up as a positive model for democracy in the Sahel until last year, when a military coup toppled the country's president.
Political turmoil took place against a backdrop of an uprising by gunmen in the desert north, where people have complained that the southern-dominated ruling class has neglected them.
The Tuareg-led separatist rebellion gained ground after the coup but was soon hijacked by a mix of Islamist groups, who imposed sharia, Islamic law, across the north before they retreated in the face of the French-led advance.
"There must be clear rules and conditions for self government in the north, guarantees that the budget will not work against the northern people, guarantees for public investment even in the north - schools, hospitals," Prodi said.
Though Mali's conflict and instability are currently at the forefront of the Sahel region's concerns, Prodi said that his ultimate goal as envoy is to foster development and long-term growth.
"Sahel is by far the poorest area in the world. We must take strong action to try to link Sahel to the rest of Africa," Prodi said.
Prodi said that his brief is limited above all to Mauritania, Burkina Faso, Mali, Niger and Chad, though the Sahel includes also Senegal, Sudan and even Eritrea.
Last year a drought created a food crisis that hit more than 16 million people in the Sahel, the U.N.'s Food and Agriculture Organisation said. (Reporting by Steve Scherer; Editing by Michael Roddy)