A convoy transporting heavy mining equipment from the Malian capital Bamako to Allied Gold's Sadiola mine came under attack in the Kayes region over the weekend, two people familiar with the incident told Reuters late on Tuesday.

The attack points to expanding security risks - and related additional costs - facing mining companies operating in military-led Sahel states that are struggling to contain Islamist militant groups.

While government and military convoys more frequently come under attack in Mali, attacks on mining equipment have until now been rare.

The CEO of Canadian gold miner Fortuna this month told Reuters that increased security concerns due to jihadist threats were among the reasons the company recently decided to exit Mali's neighbour Burkina Faso.

In Sunday's attack, two large trucks were set alight, an excavator was damaged and two pick-up trucks were stolen, one of the sources familiar with the incident said. No group has yet claimed responsibility for the attack.

The equipment belongs to the local Caterpillar dealer Neemba and had been leased to the subcontractor Mota-Engil, which operates at Sadiola's quarry, the sources said.

Eight people present - all employees of Neemba - were unharmed in the attack, which the sources said was disrupted by soldiers from the Malian army who had been nearby.

The incident took place between the towns of Diema and Sandare, the sources said. A separate security source confirmed an attack had taken place in that location on Sunday, but was unable to provide further details.

Spokespeople for Allied Gold, Neemba and Mota-Engil and a spokesperson for Mali's army did not immediately respond to requests for comment.

Mali is one of Africa's largest gold producers, with mining companies including Barrick Gold, B2GOLD, Resolute Mining, Endeavour Mining and Hummingbird Resources active in the gold-rich western and southern regions.

In February 2024, three employees of the Canadian miner B2Gold were killed in an attack on a convoy transporting them from the Fekola gold mine in southwest Mali to Bamako, the company said at the time.

But two sources with knowledge of that incident told Reuters the buses had been mistaken for a military convoy.

Mali, Burkina Faso and Niger have experienced coups in recent years carried out by military officers who vowed to push back jihadist groups affiliated with Al Qaeda and the Islamic State, though rampant insecurity persists in all three countries.