Like a pair of hunting dogs, two pick-up trucks packed with Tuareg soldiers race across the savannah, kicking clouds of sand into the blistering desert air. A band of brothers from a tribe of nomadic Saharan pastoralists, these men have stayed loyal to the state during a coup last year, an uprising by rebels from among their own people and then a deadly Islamist insurgency. Now they work as scouts for the French-led mission to purge Mali of its Al-Qaeda-linked militants and return the country to government control. Sitting around a machine gun, three on each side with legs dangling out of the truck and two in front, the Tuaregs accompany the French forces everywhere in northern Mali, serving as interpreters, guides and, when required, as combatants. Behind his white turban and fake Ray-Ban sunglasses, Tuareg Warrant Officer Alo Mazzak Ag Namaka waits for his men to finish making green tea, sitting in the shade of an acacia tree in the Inais Valley in northeastern Mali. "Before the coup in Bamako it was good, we were handling the terrorists. But then there were too many of our enemies and weapons flooded in from Libya, and we couldn't do anything. Then we left." Led by their commander, Colonel Alaji Ag Gamou, about 400 Tuareg troops withdrew in March 2012 to neighbouring Niger after their defeat by the armed militants, including the separatist Tuareg National Movement for the Liberation of Azawad (MNLA). They returned, however, after French troops liberated Mali's north from its occupation by Islamist fighters in January. Paris has since begun to understand what the Tuareg soldiers bring to the table, recognising their value as insiders who know the terrain intimately and can speak to locals, and each French unit now takes more than a dozen Tuaregs on each offensive. For Colonel Bruno Bert, who has been in command for nearly a week of a sweep of the Inais Valley, a stronghold of the Islamist Movement for Oneness and Jihad in West Africa (MUJAO) near the northern city of Gao, their contribution is vital. "These are our scouts. They have an intimate knowledge of the land and the people," he said. "People can lie to the French -- but not us""They help us find secondary roads which are less likely to be mined, for example. We have our topographical information, but nothing replaces human knowledge. "The other day we came across someone we thought was behaving suspiciously and they were able to tell us 'no, this is normal, it is an agricultural activity'." At the height of the afternoon French armoured trucks approach a village in the valley. Before entering, they mount a speaker on tripods and an officer hands one of the Tuaregs a sheet of paper on which he has written: "The terrorists are the cause of your misfortune. Do not help them or you will be accomplices. Do not block ongoing operations. Show us the weapons caches." The scout takes the sheet and, speaking authoritatively into a microphone, translates what is written into Tamashek, the language of the Tuareg people. At dusk, two more pick-ups arrive near the French command post. Chief Warrant Officer Aman Ag Nani and his men, who have brought combat rations and boxes of mineral water, are about to dig in for the night. "We know the whole of northern Mali," he says, smiling under his thick moustache. "In every team, there are one or two of us who are local. We know everything. People can lie and hide things from the French, but not us. "We serve primarily as guides but if we have to fight, we're there. We don't leave our post. Why would we? If someone has come to help you, why let him fight on their own?" Nani empties three tablespoons of sugar into the tin teapot. Behind him the Land Cruiser is packed with water containers, ammunition boxes, mats and blankets, branches for the fire and a 500-litre (110-gallon) fuel barrel. The officer is from Kidal, the cradle of Mali's Tuaregs principally run by MNLA rebels and patrolled by 100 French soldiers. "In actual fact, they are all the same terrorists. They have just exchanged the banner of (Islamist militia) Ansar Dine or Al-Qaeda in the Islamic Maghreb for the flag of the MNLA. They can fool the French, but not us. We know them all, each and every one."