At least militants killed 15 members of Mali's security forces in an attack on a camp in the centre of the country on Sunday, underlining France's case as it attempts to dissuade the United States from pulling its troops out of Africa's Sahel region. "At least 15 Malian military were killed Sunday in the Sokolo military camp during an attack by terrorists," a Malian military source said. A local politician said those killed were all gendarmes. Sokolo is located in central Segou region where extremists groups linked to Al Qaeda are known to operate. The attack came as France's defence minister left for Washington to convince officials to keep US soldiers in West Africa. Florence Parly's visit comes just days after her tour of the Sahel region, a vast arid expanse in West Africa where states have little more than nominal control, allowing extremist militant groups to flourish. Paris and its allies consider the region increasingly critical for ensuring Europe's security against extremist threats and for stemming an unchecked flow of migrants across the Mediterranean. The United States has been a key ally for France's 4,500-member Barkhane operation, providing intelligence and surveillance via drones as well as in-flight refuelling and logistical transport, at a cost of $45 million (Dh165m) a year. "The American commitment to the region is essential because they provide critical capabilities, some of which cannot be replaced," said an official in the French presidency. But President Donald Trump insists the US must focus on containing Russia and China, with Africa seen as less of a direct threat – and one that should be left to France and the European Union. American military chiefs have confirmed they are considering a drawdown of troops from Africa. "I want to make sure, as we look at counterterrorism, that I first and foremost am addressing threats to the homeland," US Defence Secretary Mark Esper said last week. General Mark Milley, chairman of the joint chiefs of staff, has said a decision on the deployment of 7,000 US special forces in Africa, particularly those in the Sahel, could come by early March. "The question that we are working with the French on is the level of effort we are supporting the French with," he said. "Is it too much? Too little? About right?" President Emmanuel Macron admitted a US pullout would be "very bad news," after a summit with France's five Sahel partners earlier this month – not least because EU nations have shown little enthusiasm to join the fight. France first deployed forces in 2012 to counter an extremist insurgency across much of Mali's north. Since then the operation has been expanded to Mauritania, Burkina Faso, Niger and Chad, tasked with building up a homegrown G5 Sahel force capable of fighting the jihadists on its own. Prominent US politicians such as Republican Senator Lindsey Graham have urged Mr Trump to uphold the Africa missions, warning of the risk of increased terror attacks in the Sahel and beyond. "As Florence Parly reiterated during her recent Sahel visit, we have to make sure a strategic rebalancing doesn't hamper our efforts in the Sahel," French army chief of staff spokesman Colonel Frederic Barbry said. But critics say local forces remain woefully outmatched by insurgents who have staged increasingly brazen and deadly attacks in recent months. They also point to a long history of corruption and authoritarian rule in the region, which has corroded faith in local governments while sapping public support for France's military engagement. Pressure has also mounted on Paris since 13 soldiers were killed in a helicopter collision while pursuing militants in Mali last month, the deadliest toll for France's military in nearly four decades.