Libya convoys: Escape route across the desert
After reports that Col Muammar Gaddafi's security chief was among former regime supporters in convoys fleeing south into Niger from Libya, the BBC's Becky Branford explores the challenges of traversing this vast expanse of Sahara desert.
Getting a large convoy of former regime officials and supporters out of Libya and into Niger would require local knowledge and logistical support, experts say.
South of Sabha - the southernmost remaining Gaddafi stronghold, from where it is assumed the convoys departed - the roads are primitive but well-established, used by civilians, the military and others such as Tuareg nomads, says BBC regional analyst Mohamed el-Doufani.
These convoys were not alone, with Niger officials speaking of "waves" of Gaddafi loyalists - mostly Tuareg fighters - coming across the border as the tide turned against the colonel in Libya.
Those planning to lead these convoys of vehicles - possibly including former regime officials and a cargo including a large amount of money to pay any bribes necessary to ease the passage - would surely have relied on local expertise to see them safely across the Sahara desert, says Mr Doufani.
Surprisingly, there is little local knowledge of this kind in the Libyan army, he says, due to a disastrous reorganisation in the 1980s which saw much military expertise lost.
It has not been confirmed whether the convoys travelled directly into Niger from Libya or looped around through the eastern corner of Algeria.
Akli Sh'kka, a Tuareg activist living in exile in the UK, says he is convinced it would have been easier, and more secure, for the convoys to go via Algeria - with a flatter, more easily traversable terrain of sand dunes - than directly into Niger, where he says the landscape is craggier and gangs are more prevalent.
But Mr Doufani says although borders are somewhat undefined in this desert zone, it would have been riskier to cross into Algeria and he suspects they would not have taken the chance.
In the past, Col Gaddafi backed Tuareg movements, including those from northern Niger, and it appears likely Tuaregs were in the convoy - including Agaly ag Alambo, a major Tuareg rebel from Niger who fought for Col Gaddafi.
The convoys may have used traditional navigation techniques - such as the stars, for example - to keep them on course for the Niger border. But Mr Sh'kka believes it is more likely they relied on modern methods such as GPS.
The convoys would have had to stock up on food, water and fuel for the perilous passage through the desert. But, as Mr Sh'kka points out, they were met at the Niger border by the Niger army, so had less than a day's passage before they were met and escorted into Niger. They apparently met no opposition from Nato, observers note.
They went on to the desert city of Agadez, which is connected by road to the capital Niamey.
But under the glare of international scrutiny, many questions remain: who exactly was on board these convoys, and where will they go next?