WASHINGTON — About 100 U.S. troops have deployed to the West African country of Niger to help establish a drone base for surveillance missions, in the latest step by the United States to aid French forces battling Islamic militants in neighboring Mali.
In a letter to Congress on Friday, President Obama said the deployment would "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."
The last 40 American troops in the deployment arrived in Niger on Feb. 20 with the consent of the government, Obama said.
A senior U.S. officer described the troops as a security unit that will protect crews flying and maintaining U.S. Air Force drones now operating from an airfield near the capital, Niamey. The force includes drone pilots, intelligence liaison officers and aircraft maintenance personnel, the officer said.
"We're basing drones there to help the French, and this deployment is the security element," the officer said.
He spoke on the condition of anonymity because he was not authorized to discuss details of the operation publicly.
French forces have been battling to push Islamic militants out of northern Mali in recent weeks in an effort to oust insurgents who seized local control after the civilian government collapsed last year.
Predator drones are already flying over Mali to assist French troops, who intervened in January and have driven back militants and Tuareg rebels, who had taken over three major cities and were threatening Mali's capital, Bamako.
The drones flying from Niger will be unarmed surveillance aircraft tracking suspected militants operating in the remote parts of northern Mali. The aircraft could also be used over other countries in the region, the officer said.
The Obama administration has not yet decided to establish a permanent drone base in Niger, the senior officer said. For the moment, the operation is considered a temporary mission to assist the French.
But some senior officers in the Pentagon's Africa Command, which oversees military operations on the continent, favor a permanent base to develop a better picture of the militant threat in West Africa, the officer said.
Among the groups the U.S. is worried about is Boko Haram, an Islamist extremist group in neighboring Nigeria.
Currently, the only permanent base in Africa from which drones operate is in Djibouti, thousands of miles to the east.
In addition to the militants in Mali — some with loose ties to Al Qaeda groups — extremists have taken refuge in the largely ungoverned desert areas of southern Libya and Algeria.
If the Obama administration decides to authorize a permanent base in Niger, it would probably be in Agadez, near northern Mali, the officer said, confirming a report in the New York Times.
Some senior military commanders, in arguing for a permanent base, say the militant threat in the region is growing and could eventually threaten the U.S. and its allies unless more aggressive action is taken.
But some Obama administration officials are skeptical about getting more deeply involved in the region, saying there is no strong evidence that militants there want to target the United States.
Some officials also argue against getting involved in a low-level military operation just as direct U.S. involvement in the war in Afghanistan is nearing an end.
The Obama administration has helped the French operation in Mali with intelligence, transportation for French troops and air refueling of French fighters. But the White House has kept the U.S. role limited.
The U.S. buildup in Niger, though still small in numbers, has unfolded quickly. Last month, the U.S. and Niger signed an agreement outlining legal protections for American troops operating there.
The U.S. also has been operating surveillance drones across the region, including over a natural gas complex last month in eastern Algeria, where militants took hundreds of people prisoner during a four-day siege that killed 37 hostages.