Forty people were killed and 85 were injured when two buses crashed in a head-on collision overnight on an arterial road in Senegal's central Kaffrine region, the government said on Sunday.
Images of the incident showed the completely mangled front end of a white bus, with blood-flecked seats, personal items and a shoe strewn around the tree-lined crash site.
Road accidents are common in Senegal, largely because of driver error, poor roads and decrepit vehicles, say experts, but the latest disaster has caused one of the heaviest losses of life from a single incident in recent years.
In a statement, the government announced three days of national mourning beginning Monday, with flags to be flown at half-mast throughout the country.
President Macky Sall will visit the crash site just outside of the village of Sikilo on Sunday, it said.
"In view of this tragedy, the head of state extends his deepest condolences to the families of the victims and wishes a speedy recovery to the injured," the government said.
Public prosecutor, Cheikh Dieng, said in a statement that early investigations suggested a public passenger bus suffered a burst tyre and swerved off course.
It then crashed "head-on with another bus coming in the opposite direction", he said.
'Tragic'
The statement said the incident happened around 0330 GMT.
It is "a tragic accident," Kaffrine mayor Abdoulaye Saidu Sow, who is also the Minister of Urbanism, told AFP.
Speaking from Kaffrine, he said President Sall would be joined there by the prime minister and several other ministers on Sunday.
Opposition politician Ousmane Sonko announced on Twitter that he would postpone a scheduled fundraising program in light of the accident.
"We bow before the memory of the deceased, offer our very sincere condolences to their grieving loved ones and to all Senegalese and pray for the merciful rest of their souls as well as a speedy recovery for the injured", he said.
Colonel Cheikh Fall, who heads operations for the National Fire Brigade, told AFP the victims were taken to a hospital and medical centre in Kaffrine.
The wreckage has since been cleared and normal traffic has resumed on the road, he said.
The governor and local officials have visited the scene, he added.
In a tweet, President Sall said that after the period of national mourning finished, a government council will be held to "take firm measures on road safety".
In October 2020, at least 16 people were killed and 15 more injured when a bus collided with a refrigerated lorry in western Senegal.
The bus, with a 60-seat capacity, was heading to Rosso near the border with Mauritania, the fire brigade said, adding that the number of people onboard was unknown.
Local media said at the time that the truck was hauling fish to Dakar.