Semafo ramped up its security past year after attacks near its two mines in the country.
Canadian gold miner Semafo said on Wednesday several people had been killed when a convoy transporting some of its workers was attacked on a road in eastern Burkina Faso.
The ambush underscores the deteriorating security situation in Burkina Faso, which observers say has increasingly become a refuge for jihadis from neighboring Mali and Niger.
On Wednesday morning "unidentified armed individuals" ambushed five buses carrying local employees, contractors and suppliers of the Samafo mining company, said Saidou Sanou, the governor of the country's Est Region.
The company would like to express again its honest condolences to families of the victims in addition to its firm support of Burkina Faso's security forces.
The mine itself, it added, remains secure and its operations had not been affected.
In a separate statement, Geodrill Ltd said two of its employees were killed in the incident. Last year, an employee and subcontractor were killed when a bus was targeted by bandits, according to Canadian Press.
The country, which experienced its first major extremist attack in 2015, is a gateway south into coastal West Africa, and regional leaders worry the extremists could be moving into Togo and Benin.
Reports indicate that hundreds of people have been killed so far this year and more than 150,000 have fled their homes due to attacks across the Sahel region.
However, at least three known militant groups operate in Burkina Faso: the Group for the Support of Islam and Muslims (linked to al-Qaeda), the Islamic State in the Greater Sahara Group and locally-rooted Ansarul Islam.
The country's badly equipped, poorly trained and underfunded security forces have been unable to stem the violence, which has intensified throughout 2019 to become nearly daily.
Once peaceful, Burkina Faso has been suffering from a rapidly deteriorating security situation: since 2015 at least 500 people have been killed and almost half a million people are internally displaced.