United States troops are in Chad training some of the country's elite forces in how to fight al-Qaeda or any of its allies in the region.
By Martin Plaut
BBC correspondent in Chad
The US is giving equipment as well as training to the soldiers
This is the latest battleground in what United States President George W Bush calls the global war on terrorism.
Twenty-five US marines have been stationed at a base 50km south of the capital Ndjamena at a military base, Camp Loumia, working with 170 Chadian soldiers.
It is all part of what the US calls the Pan-Sahel Initiative, with US forces improving military training in Chad, Mali, Mauritania and Niger.
Before he set off for last year's tour of Africa, Mr Bush declared security to be the first priority of what he said was a partnership with African states.
"We will give them the tools and resources to win the war on terror," he said.
Those words are now being put into action and Major Paul Baker is in charge of this operation.
"The enemy is anyone who passes illicit arms, goods or people, through the territory of Chad. Predominantly up in the north, where the borders are a little more porous, there is a little more of a threat of terrorism.
Ultimately this company is the anti-terrorism unit for Chad," he said.
The US had almost lost interest in Africa following the end of the Cold War.
But since 11 September 2001, the continent is now firmly back on the Pentagon's agenda as a breeding ground for terrorism.
The train bombs in Madrid earlier this year, planned from Morocco, only underlined how dangerous this region could be.
At a firing range, a machine gun provides covering fire for the advancing Chadian troops, under supervision from marine instructors.
The aim is to provide basic infantry skills to the Chadian troops.
This is because when the Chadian army went into action in March many of its casualties were victims of friendly fire - shot in the back by their own side as they advanced.
That was when trucks were spotted by US intelligence driving across the barren wastes of the Sahara.
On board were members of the Salafist Group for Preaching and Combat , an Algerian Islamic militant group associated with al-Qaeda.
In the ensuing clash Chadian forces, re-supplied by the US, killed 43 members of the group, laying the foundation for closer co-operation between Ndjamena and Washington.
Major Abakar Mohammed Abdullah is the Chadian officer who will command the battalion when the marines leave.
He sees his newly trained troops as forming the backbone of a network of units co-operating across the Sahel.
"Chad is ready to co-operate with neighbouring countries to combat the Salafist group - especially Niger, because the Salafists came through Niger, so we are ready to co-operate with Niger to fight the Salafists."
But the real problem with US's Pan-Sahel Initiative is that it could release monsters never dreamed of by Washington planners.
Al-Qaeda was, after all, a product of US strategy to arm the
Mujahedeen and tear Afghanistan from the grasp of the Soviet Union.
The Chadian government is hardly a squeaky-clean democracy.
Major Baker accepts that Africa can throw up difficult allies.
"You never know. Africa is a fluid environment - coups and dictatorships all the time. You never know who you are training today, what he will do tomorrow."
As evening falls, it is a time for the marines to relax, and lose a little money to each other at poker.
For many it is their first time in Africa and much is very new - including the quality of the Chadian troops they are working with.
Corporal Lameen Whitter found this hard to accept.
US soldiers were surprised by the Chadians' mis-matched uniforms
"Their uniforms were mis-matched. Some had no uniforms at all. Not looking very unified, not very clean-cut, as we are used to. That was a shocker," he said.
Now the Chadian soldiers have new uniforms and boots, guns and ammunition, and new skills that could make a difference in combating the threat that America fears most.
But Africa has shattered the dreams of many a foreign power.
Finding reliable partners in the complex and changing maze of this continent's politics is no easy task.
In future the US could find its new friends very troublesome indeed.