The United States on Thursday designated Mali-born preacher Amadou Koufa as a terrorist, putting a new focus on stopping the militant blamed for multiple attacks on Western interests in the Sahel.
Koufa -- a member of the Fulani, a long-impoverished herding community -- has won a following among the young with fiery sermons urging a hardline form of Islam that have been disseminated widely by mobile app WhatsApp.
He is a senior figure in the JNIM, or Group to Support Islam and Muslims, which has sworn allegiance to Al-Qaeda in the Islamic Maghreb.
The State Department said the alliance, itself designated as terrorist last year, is to blame for the deaths of more than 500 civilians since 2017.
Notable incidents include a 2017 attack on a resort popular with foreigners on the outskirts of Mali's capital Bamako and twin March 2018 attacks in Burkina Faso on the French embassy and military headquarters.
The designation -- which makes any dealings with Koufa a crime in the United States -- came two days after France said it had killed another top JNIM leader, Ali Maychou.
Secretary of State Mike Pompeo hailed the French raid, writing on Twitter: "We must continue to work together to seek out and destroy terrorists wherever they may be."
A senior State Department official said that both Al-Qaeda and the Islamic State group still posed major challenges in the region.
The United States hopes to "prevent the violence and instability that we're seeing in Mali from spreading into littoral regions of Africa," he said on condition of anonymity.
"We can't afford to have this contagion spread, so we're working very closely with our partners to pressure these ISIS and Al-Qaeda affiliates," he said.