A U.S. Army Special Forces weapons sergeant speaks to a group of Nigerian soldiers during Exercise Flintrock in March in Diffa, Niger. The U.S. military said Wednesday troops killed 11 Islamic State fighters in a December attack. Photo by Spec. Zayid Ballesteros/U.S. Army/UPI

March 15 (UPI) -- U.S. military forces in Niger killed nearly a dozen Islamic State terrorists three months ago when they were attacked in the west African country, Pentagon officials said.

The U.S. forces were in Niger to set conditions for future operations "against violent extremist organizations in the region," Pentagon spokeswoman Maj. Sheryll Klinkel told CNN, noting that the U.S. personnel were not there to pursue enemy combatants.


Eleven militants were killed in the firefight, including two who wore suicide vests, Klinkel said. No U.S. personnel were injured. A large weapons cache was also destroyed in the fight.

"Our forces do operate in unstable areas and are occasionally exposed to danger from enemy forces," Klinkel said. "When such a situation occurs, our personnel are authorized to respond to threats and violence appropriately."

The firefight, first reported by The New York Times, happened just two months after four U.S. green berets and five Nigerian soldiers were killed in another Islamic State ambush.

U.S. Africa Command (AFRICOM) said the new battle occurred Dec. 6 in the country's Lake Chad Basin region. AFRICOM spokeswoman Samantha Reho said no U.S. or Nigerian forces were killed or injured.

Although both attacks were carried out by Islamic State-affiliated militants, authorities said they were different factions.

"Based on currently available information, we assessed this attack was launched by ISIS-West Africa," Reho said.

AFRICOM conducted an investigation into the first ambush, which is still under review at the Defense Department.