At least 31 people in a bus ferrying to a local market were massacred by Militants in central Mali on Friday when they open fire on the bus, local authorities say. This is the latest deadly attack in a region racked by violent insurgency.

The bus was targeted by unidentified gunmen as it traveled its twice-weekly route from the village of Songho to a market in Bandiagara, 10 kilometers away, said Moulaye Guindo, mayor of the nearby town of Bankass.

“Armed men … shot at the vehicle, slashed the tires, and shot at the people,” Guindo said.

He and another local official, who spoke on condition of anonymity, said at least 31 people were confirmed dead with many more wounded or missing.

The villages sit in the heart of the Mopti region, an epicenter of violence in Mali fuelled by insurgents linked to al Qaeda and the Islamic State.

An internal security memo, shared by a source, said first responders to the scene of the latest attack discovered 25 burned bodies in the truck.

Images circulated on social media showed the smoldering frame of a passenger bus filled with bodies, still slumped over in their seats. Reuters could not independently verify the authenticity of the images.

Jihadist attacks have surged across Africa’s Sahel region, killing thousands and displacing millions across Mali, Burkina Faso, and Niger.

The UN mission Minusma has deployed about 13,000 troops to try to contain the violence, while France is in the process of drawing down a counterinsurgency force, from around 5,000 troops to around 3,000, supported by a mix of European Special Forces and focused on training the Malian army.

Minusma has recorded more than 250 fatalities since it started in 2013, making it the most dangerous UN peacekeeping mission in the world.

Unidentified armed men attacked a convoy belonging to the United Nations peacekeeping mission in Mali on Friday, killing one civilian worker and wounding another, the mission said.

The convoy was traveling from the northern city of Kidal to Gao and came under fire about 100km (62 miles) northeast of the town of Bourem, the mission said.

Armed attacks by Islamist militants and other groups are common across vast swathes of Mali, despite a heavy presence of international troops.