Scores of people have died after becoming engulfed in a huge fireball which was sparked after a collision between a fuel truck and another truck in the capital of Sierra Leone.

Authorities say the inferno ignited after the ruptured tanker began leaking its load and people rushed forward to collect the spilling fuel.

At least 100 people were killed in the raging blast which blazed through shops and houses at a busy junction at the edge of Freetown, and more than 100 have been wounded.

Media and authorities have described horrific scenes with charred and badly burnt bodies lying in the streets and trapped in blackened cars.

Authorities declared the accident in the suburb of Wellington as a national disaster and promised free medical treatment for casualties who have been admitted to hospitals and clinics across the city.

“We’ve got so many casualties, burnt corpses,” said Brima Bureh Sesay, head of the National Disaster Management Agency, in a video from the scene shared online.

“It’s a terrible, terrible accident.”

Freetown Mayor Yvonne Aki-Sawyerr said on Facebook she was “saddened.”

“The video and photo footage making rounds on social media are harrowing,” wrote Ms Aki-Sawyerr.

“My sympathies go out to the families and loved ones of the victims of the explosion. May the souls of the departed rest in perfect peace.”

Burnt vehicles in the aftermath of the explosion at a busy junction in Freetown Photo: Getty

Accidents with tanker trucks in Sub-Saharan Africa have previously killed scores of people who gathered at the site to collect spilled fuel and were hit by secondary blasts.

In 2019, a tanker explosion in eastern Tanzania killed 85 people, while around 50 people were killed in a similar disaster in Democratic Republic of Congo in 2018.

The mayor said that the extent of the damage in Freetown was not yet clear, adding that police and her deputy were at the scene to assist disaster management officials.

“My profound sympathies with families who have lost loved ones and those who have been maimed as a result,” President Julius Maada Bio tweeted.

“My government will do everything to support affected families.”

Security forces take control at the scene of the terrible explosion. Photo: Getty

Sierra Leone’s National Disaster Management Agency (NDMA) told CNN in a statement the truck crash occurred when the fuel tanker was about to enter a nearby filling station to discharge its fuel.

“Footage and eyewitnesses intimated that while the collision took place, both drivers came out of their vehicles and warned community residents to stay off the scene while trying to address a leakage emanating from the collision,” the statement said.

The NDMA said “some community members rushed to the scene and took advantage of the leakage to scoop fuel and store it in nearby makeshift structures.”

“In the cause of scooping the fuel, there was a major explosion that resulted in the fire disaster that occurred,” it said.

Sierra Leone’s National Disaster Management Agency (NDMA),

-with AAP