The United States is building a drone base in Niger’s Sahara desert to help in the battle against extremists in the Sahel region.

The Niger Air Base 201 under construction a few miles outside Agadez already has three hangars and the first layers of a runway, reports VOA.

Built at the request of Niger’s government, the air and drone base will host fighter jets and MQ-9 drones which will be transferred from the capital Niamey.

The drones can survey and strike several West and North African countries with their wider range. The project cost $110 million and according to Air Force officials, it is the largest troop labour construction project in U.S. history, reports VOA.

The report added that it will cost $15 million annually to operate the base which is the second largest U.S. military presence in Africa behind the only U.S. base in Djibouti.

Niger hosts about 800 U.S. military personnel with 500 of them working at the new base against Djibouti’s 4,000 personnel.

Last year, four U.S. soldiers and five Nigeriens were ambushed and killed by extremists linked to the Islamic State group. This brought to light the unknown military presence in the country which is in the middle of an Islamist insurgency war.

The U.S. said the drones at the base will target the several affiliated al-Qaeda and Islamic State groups in the Sahel countries including the Lake Chad region which is battling with the spread of Nigeria’s Boko Haram insurgency.

Local Nigerian officials and civil society have expressed concern about the increased U.S. military presence in their country.

“We are afraid of falling back into the same situation as in Afghanistan, with many mistakes made by American soldiers who did not always know the difference between a wedding ceremony and a training of terrorist groups,” said Amadou Roufai, a Nigerien administration official.

For civic leader Nouhou Mahamadou who spoke to the VOA: “The presence of foreign bases in general and American in particular is a serious surrender of our sovereignty and a serious attack on the morale of the Nigerien military.”

Commander Brad Harbaugh, who is in charge of the new base assured that the drones will gather intelligence that can be used by Niger and other U.S. partners to prosecute extremists.