The Perenti employees killed or wounded worked for its African Mining Services unit, which had been contracted by Semafo for work at its Boungou mine.
The company said those numbers were yet to be officially confirmed. It added that its work at the Boungou mine was suspended and it was planning to send staff back to their homes and assess the impact of the suspension on its earnings guidance for the 2020 financial year.
In a separate statement, Geodrill said two of its employees were killed in the incident.
It remains unclear how many people were in the convoy, what their nationalities were or how many were missing. But two security sources said dozens may still be unaccounted for.
The identity of the assailants was unclear, but Burkina Faso is struggling to combat surging Islamist violence in remote eastern and northern scrubland areas of the West African state.