Investigators on the ground probe deadly Niger ambush Eyewitnesses give accounts of how they found Sgt. La David Johnson’s body after the attack; Kristin Fisher has the details for ‘Special Report.’Video

American forces in Niger were the targets of yet another terrorist ambush, a December attack disclosed by U.S. Africa Command on Wednesday — the latest revelation coming amid the fallout from a deadly October ambush and as lawmakers increasingly question the U.S. mission in the African country.

U.S. Africa Command said the Dec. 6 ambush, in which 11 ISIS fighters were killed and no U.S. or Nigerien troops were injured, happened in the Lake Chad Basin area during a mission to “set the conditions for future partner-led operations against violent extremist organizations in the region.”

“A combined force of Nigerien and U.S. military members came under fire from a formation of violent extremists,” Africa Command said in a statement to Fox News. “We assessed 11 enemy killed in action, including two wearing suicide vests, and one weapons cache destroyed during this mission.”

The December incident followed an October attack in which four U.S. soldiers were killed after their convoy in Africa was hit by rocket-propelled grenades and heavy machine gun fire.

About 50 Islamic extremists ambushed the group of U.S. and Nigerien troops in that attack, wounding two additional Americans and killing 10 Nigeriens.

The team reportedly was in unarmored trucks when the ambush occurred on a return route from the capital city of Niamey. The group was ambushed by ISIS-affiliated militants traveling by vehicle, and the terrorists were likely tipped off by local villagers.

Gen. Joseph Dunford, Chairman of the Joint Chiefs of Staff, said air support wasn’t requested for the attack area until an hour after the ambush began. It took two French Mirage fighter jets 30 minutes to respond to the request, and the jets weren’t overhead until two hours after the battle began.

After the ambush made headlines, several lawmakers expressed concern with decisions leading up to the attack — while others in Washington admitted being surprised there were any U.S. troops in Niger.

Fox News’ Lucas Tomlinson and Kaitlyn Schallhorn contributed to this report.