At least 40 people were killed and dozens more were injured when two buses crashed in central Senegal early on Sunday.

One public bus punctured a tire on the road in the central Kaffrine region, which caused it to swerve uncontrollably and cross over into the other side of the road, the public prosecutor said.

It then crashed with another bus coming from the opposite direction.

At least 78 people were injured, with some in serious condition, the public prosecutor said.

How did the president react?

Senegalese President Macky Sall offered his condolences to the families of the victims.

"I am deeply saddened by the tragic road accident today in Gniby causing 40 deaths and many serious injuries," he said in a tweet on Sunday.

Sall declared a three-day state of mourning starting Monday.

The president also vowed to hold an inter-ministerial council on road safety on the same day.

Road accidents are common in Senegal due to poor road and vehicle conditions as well as driver error. However, the latest accident is the most serious in years, with a significantly high death toll.

At least 25 people were killed when two buses crashed in 2017. One of the buses was carrying Muslim pilgrims headed for the central town of Touba.