About 100 American troops have been deployed to the African nation of Niger, where a US defense official said they would be setting up a drone base for surveillance missions.

PresidentBarack Obama announced the deployment Friday in a letter to Congress, saying that the forces “will provide support for intelligence collection and will also facilitate intelligence sharing with French forces conducting operations in Mali, and with other partners in the region.”

French troops have been fighting Islamic militants in Mali, which neighbors Niger. The drone base will allow the US to give France more intelligence on the militants. Over time, it could extend the reach not only of American intelligence-gathering but also US special operations missions to strengthen Niger’s own security forces.

The drones at the Niger base will be unarmed and used for surveillance, not airstrikes.

Obama said in his letter to Congress that the US forces has been deployed with the consent of Niger’s government. The forces were also deployed with weapons “for their own force protection and security,” the president said.

Last month, the US and Niger signed a status-of-forces agreement spelling out legal protections and obligations of American forces that might operate in Niger in the future.

Africa is increasingly a focus of US counterterrorism efforts, even as al-Qaeda remains a threat in Pakistan, Yemen and elsewhere.

A number of al-Qaeda-linked Islamic extremist groups operate in Mali and elsewhere in the Sahara, including a group known as al-Qaeda in the Islamic Maghreb, or AQIM, which originated in Algeria and is active in northern Mali.