The Tongo Tongo ambush or the Niger ambush occurred on 4 October 2017, when armed militants from the Islamic State in the Greater Sahara (ISGS) attacked Nigerien and US soldiers outside the village of Tongo Tongo, Niger, while they were returning to base after a stop in the village.^[20] During the ambush, four Nigeriens, four US soldiers, and at least 21 ISGS militants were killed, and eight Nigeriens and two US soldiers including the team commander were wounded. In the day preceding the ambush, the Nigerien and US soldiers conducted a mission attempting to locate and capture or kill Doundou Chefou, a commander in the ISGS.^[21]

The ambush sparked political debate over the presence of US forces in Africa and brought attention to previously under-reported US military activities in the region.^[22] The ambush also prompted congressional inquiries, and an investigation by the US Department of Defense (DoD).^[23] The DoD inquiry, completed in 2018, found that the 11-member US special forces team was not prepared for the mission, and identified other flaws in planning.^[20]

The ambush remains the largest loss of American lives in combat in Africa since the Battle of Mogadishu in 1993.^[1]