The blast happened when a fuel tanker collided with another truck at a petrol station on Friday night, according to witnesses.
The flames then spread, burning people in cars and on roads nearby.
The majority of the victims were street vendors and motorcyclists, many of whom were caught in the blaze while trying to retrieve fuel leaking from the tanker before it ignited, according to volunteer worker Jusu Jacka Yorma who was at the scene.
The National Disaster Management Agency said in a statement that 98 deaths had been recorded so far and “92 survivors are currently admitted to various hospitals in Freetown”.
Vice-President Mohamed Juldeh Jalloh had earlier given a death toll of 98 after arriving at the scene, adding that all those injured would receive free treatment.
A nurse at a hospital where victims were sent told AFP that many women, men and children had sustained “serious injuries”.
Rescue operations continued under police supervision on Saturday.
Hundreds of people gathered at the scene of the tragedy, many searching for missing relatives under the eye of security forces, an AFP correspondent said.
Contrary to some initial reports, a fuel depot near the accident did not explode, the correspondent added.
Video footage showed a burnt-out tanker and a truck, and the surrounding area littered with husks of vehicles, some still smouldering.
“Deeply disturbed by the tragic fires and the horrendous loss of life,” President Julius Maada Bio wrote on Twitter.
“My profound sympathies with families who have lost loved ones and those who have been maimed as a result. My government will do everything to support affected families.”
The United Nations office in Sierra Leone expressed its “deepest condolences” to the victims.
“The UN family closely monitors the situation and stands ready” to help with the response to the fire,” it said in a statement.
– ‘Harrowing’ footage –
Freetown mayor Yvonne Aki-Sawyerr said she was “deeply saddened” by the explosion.
“The video and photo footage making rounds on social media are harrowing,” she wrote on Facebook.
“The extent of damage to property is unknown,” she said, adding she was unable to visit the scene because she was travelling abroad.
Despite being rich in diamonds Sierra Leone remains one of the world’s poorest countries, its economy devastated during a 1991-2002 civil war that left 120,000 dead.
Accidents involving petrol tankers have happened before in the former British colony of 7.5 million.
In other parts of Africa, similar incidents have also left many dead as people gather to collect leaking fuel.
In 2009, more than 100 people were killed when a petrol tanker overturned northwest of Kenyan capital Nairobi and an explosion burnt those gathering to try and grab some of the fuel.
At least 100 people were killed when a tanker exploded in Tanzania in 2019, while in 2015 more than 200 perished in a similar accident in South Sudan.
In July this year, 13 people were killed and others seriously burnt when a “huge fireball” engulfed a crowd in Kenya as they siphoned fuel from an overturned petrol truck that ignited without warning. SOURCE: AFP