Five Nigerien and three US Special Forces were killed and others wounded in an ambush on a joint patrol in southwest Niger.
The attack, which occurred on Wednesday night, marks the first US combat casualties in Niger, where Washington provides training and security assistance in the fight against armed groups in the Sahel region.
"We can confirm reports that a joint US and Nigerien patrol came under hostile fire in southwest Niger," a spokesperson of the US Africa Command told Radio France International (RFI) by telephone.
According to RFI the ambush took place after fighters from Mali attacked the village of Tongo Tongo in Tillaberi. A counter-operation was launched, but the US and Niger soldiers fell into a trap, according to the radio report.
Namatta Abubacar, an official for the region of Tillaberi, told Niger TV that five Nigerian soldiers were among the dead.
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No group has yet claimed responsibility for the attack but the area is largely controlled by fighters, including members of al-Qaeda in the Islamic Maghreb (AQIM) and the Islamic State of Iraq and the Levant (ISIL, also known as ISIS).
African security forces backed by Western troops have been stepping up efforts to counter the armed groups, which are part of a growing regional insurgency in the Sahel region.
Presidents of the Sahel countries, including Mali, Niger, Mauritania, Burkina Faso and Chad, are working on final modalities to set up a G5 Sahel force to help fight the numerous groups that are active in the region.
In mid-September, the government of President Mahamadou Issoufou extended Niger's state of emergency in force since March due to a threat coming from Mali.
Analysts said internal conflicts within Mali were complicating the fight against armed groups in the Sahel.
"What we see is a big focus on military, on equipment, on institutions that they are going to establish," Marie Roger Biloa, editor of the Paris-based Africa International, told Al Jazeera.
She said, however, that so far it has proved difficult to bring troops from different countries to effectively work together, and called for increased political efforts to address Mali's "very complicated" situation.
"The problem is that France wants to fight terror - because terrorism is striking on French soil but also abroad - but they fail to realise or to take into consideration that Mali, which is the heart of the problem, is having internal problems to solve," she said.
"If you want to be efficient you also have to address that issue."
In mid-June, Niger mounted a new military operation in the Tillaberi region to take on the armed groups.
The United Nations later warned that the conflict in Mali was spilling over to Burkina Faso and Niger, after a significant surge of attacks in border areas.
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The UN has 12,500 troops and police serving in the MINUSMA force in Mali, considered the world body's most dangerous peacekeeping mission.
In 2012, Mali's north fell under the control of groups linked to AQIM who exploited an ethnic Tuareg-led rebel uprising.
While the fighters were largely ousted by the French-led military operation, attacks have continued on civilians, the Malian army as well as French and UN forces.
Source: Al Jazeera and news agencies...Read more