At least 37 people have been killed and 60 wounded in an attack on a mining company convoy in Burkina Faso, authorities say.

Five buses carrying staff of Canadian firm Semafo were ambushed on Wednesday about 40km (24 miles) from the eastern town of Boungou, reports say, reports BBC.

A military escort vehicle was reportedly struck by an explosive device before gunmen opened fire.

It is said to be the third deadliest on Semafo staff in 15 months.

The West African country has been wracked by an Islamist insurgency that has killed hundreds of people in recent years.

The military has struggled to contain violence that spilled over the border from neighbouring Mali.

Semafo ramped up its security last year after attacks near its two mines in the country.

The latest attack happened on a road between Fada and its mine in Boungou, the company said.

The company said its operations had not been affected and offered condolences to the families of the victims, none of whom have been named.

"We are actively working with all levels of authorities to ensure the ongoing safety and security of our employees, contractors and suppliers," the firm said in a statement.

What's happening in Burkina Faso?

Jihadist attacks have increased in Burkina Faso since 2015.

The conflict spread across the border from neighbouring Mali, where Islamist militants took over the north of the country in 2012 before French troops pushed them out.

About 500,000 people in Burkina Faso have been forced to flee their homes over the past three months, according to the UN Refugee Agency.

Last month, 20 people were killed in an attack on a gold-mining site in the north.

Days later, thousands protested in the capital Ouagadougou to denounce violence in their country and the presence of foreign military forces in the region.