Burkina Faso has launched an investigation into the deaths of Nigerian Muslim pilgrims who were allegedly killed while travelling by bus to Senegal, foreign minister Olivia Rouamba said Monday.

Nigerian media reported that President Muhammadu Buhari had condemned the killing of Nigerian pilgrims who were travelling to Kaolack, Senegal. The incident had allegedly happened as the bus was passing through Burkina Faso.

During a meeting with Nigerian ambassador Misitura Abdulraheem, Rouamba assured that “investigations are opened to clarify the situation”.

“For the moment, no concrete information or evidence has been recorded on the ground that proves the veracity of the facts,” the minister said in a statement.

Rouamba added that Burkina Faso “fundamentally disapproves of the accusations made against our defence and security forces”, referring to allegations made about its army being responsible for the attack.

Burkina Faso is one of the poorest and most volatile countries in Africa.

Thousands of troops, police and civilians have been killed and around two million people have fled their homes since jihadists launched an insurgency from neighbouring Mali in 2015.

More than a third of the country lies beyond the control of the government, and frustration within the army at the mounting toll triggered two coups last year.