The US and Britain are concerned about the threats posed by Islamic militants in North Africa. A group known as al-Qaeda in the Islamic Maghreb has mounted a string of attacks, mainly in Algeria, and there is talk of them moving into southern Sahara and becoming active in Mali. Andrew Harding has been travelling in the deserts of Mali to find out what the locals think.
Timbuktu is proud of its ancient, glorious past
I was standing in a blinding white patch of desert about four hours' drive west of Timbuktu.
The air was shimmering appropriately in the heat. The camels were drifting by in their leisurely manner.
It all felt suitably remote. Then my mobile phone rang.
Modern Mali is a contradictory sort of place. Crumbling mud houses with satellite dishes on the roof. Turbaned Tuareg tribesmen, texting.
The small town of Timbuktu sits just above the sluggish brown Niger River, and just below the Sahara desert.
To stare out across the dusty rooftops towards the endless dunes, and the silence that rises from them is to feel somehow like you're in the middle of an ocean, rather than a continent.
The streets here are made of sand and rubbish. There's one local doctor. No sewage system, and on the western edge of town, Colonel Gaddafi is busy having a rather grand hotel built.
Officially this is one of the poorest places on Earth. But it doesn't quite feel that way.
There's a quiet pride here - a sense that Timbuktu has not entirely lost touch with its ancient, glorious past, when these same streets were packed with university students, and the first dehydrated European explorers had not yet crossed the desert.
Today, the salt caravans still arrive here from the mines to the north, just like they've done for centuries.
A hundred or more camels take three weeks to lurch between oases from the mines of Taoudenni, four huge slabs of crystallised salt strapped to each animal.
The miners spend the milder six months of the year scratching the surface of an ancient sea-bed with homemade axes. They live in salt huts, drink salt water, and die young.
Near the market in Timbuktu, I met a salt trader called Boujima Handak. He's 49, but looked about 70.
Boujima told me he'd been waiting for a month for his latest consignment from the mines. Trouble with the camels? I asked. No, he said. The gearbox had broken.
Lorries have started to make the round trip to the mines. They do it in a quarter of the time. In a few short years they've taken over about half the trade.
As a young man, Boujima once came so close to dying of thirst in the desert that he had to kill a camel and drink the water still trapped in its body. He shook his head and smiled at the memory. These days the lorry drivers carry satellite phones for emergencies.
And now of course, it's not just lorries criss-crossing the Sahara. Smugglers use four-wheel-drives to carry guns, drugs and people to and from Algeria and the Mediterranean coast.
The same smugglers' routes are now used by Islamist militants - mostly Algerians at the moment. They hide in the desert, do a little training and increasingly, it seems, try to earn money from kidnapping.
As a result the American government is strongly urging its citizens to stay clear of the whole of northern Mali, including Timbuktu. The British government says the town is OK, but not the desert.
I had lunch the other day at the house of a local police colonel. The governor of Timbuktu and the imam of the town's stunning 13th century mosque were also invited.
The three men argued respectfully about whether or not it would be a good thing if oil were to be discovered in Mali.
Colonel Ascofare, a rather grand 61-year-old, seemed to settle the matter.
"It would be a disaster," he declared thoughtfully. "Name me one African country that has benefited from oil. It ruins them. In Nigeria, the petrol costs more than it does here."
As for the terrorism threat, Col Ascofare nearly choked on his lamb stew. It was, all the men agreed, ridiculous, wildly exaggerated, and very bad for business.
The general view here is that the extremists, apparently now signed-up members of the al-Qaeda franchise, are a minor, containable threat.
They did assassinate an army officer in Timbuktu in June, but most people think that was something to do with money and internal score-settling.
Besides, most of the attacks have taken place in neighbouring countries, or at least deep in the desert.
Unsurprisingly though, the tourism industry has been badly hit. The Americans are staying way and numbers are down by nearly half on last year.
Halis, our guide and translator, shrugged and tinkered with his blue turban. He was born in the desert. He's not sure exactly when or where. Over the years he has built up a successful tourism business, traded in salt, married an American woman, and stayed firmly put here in Timbuktu.
Last night, we all went out by camel to sleep in the desert. After dark, the sky fills up with an almost ridiculous number of stars.
Halis passed round some tumblers of mint tea. "When I am away from this place," he said with a sudden rush of earnestness, "I think about the desert and I cry."
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