Three employees of a cement factory owned by Nigerian billionaire Aliko Dangote have been killed by gunmen in Ethiopia’s Oromia region.

Indian national, Deep Kamara, who managed the plant, died alongside two Ethiopian employees, the BBC reports.

They were returning to the capital, Addis Ababa, from the factory, a government statement said.

The motive is unclear.

Dangote is expected in the country on Thursday.

He will be holding an emergency meeting with the factory’s management, Ethiopian daily the Addis Standard reports.

Oromia has been plagued by violence for the past two years over political and economic grievances by Oromo youths – despite being the country’s largest group.

The Dangote Cement Factory was commissioned in May 2015 and is the largest such plant in the country.

The authorities were recently forced to cancel the renewal of a licence for a gold mine owned by an Ethiopian-Saudi billionaire following protests by Oromia residents.

The country remains in a state of emergency, which was imposed in February a day after then Prime Minister Hailemariam Desalegn resigned.

He was replaced by Abiy Ahmed, the first prime minister from the Oromo ethnic group, which is the largest in Ethiopia.