The blast and fire led to panic in the densely packed area of Lagos, a city of some 15 million people, with residents jumping from windows to flee and others salvaging goods from their shops in the neighbourhood’s large market.
Fireworks continued to explode well after the fire began while smoke was heavy and the blaze intense, making it difficult for rescue workers and firefighters to approach the scene.
Huge crowds gathered in the area, including onlookers and those seeking to help.
Details were still emerging, but officials said it appeared to have begun at a warehouse storing fireworks, where a fire caused a major explosion that shook parts of the sprawling city.
The fire then spread, with at least nine buildings in the neighbourhood ablaze when an AFP journalist arrived on the scene.
Residents rushed to help firefighters as they neared the fire, bringing containers of water and helping carry hoses, but the volatile situation made it difficult.
“We have treated up to 30 people so far,” Red Cross worker Nicolas Adesile told AFP at the scene, adding there had not been any reports of deaths.
One man treated for a cut on his leg said he jumped from his building to escape. “I had to jump from the first floor to save my life,” he said.
Officials were seeking to confirm further details on the incident, with the force of the explosion so strong that rumours even spread over whether there had been a plane crash.
The National Emergency Management Agency said fire was believed to have caused the explosion at a shop storing fireworks.
The shop was severely damaged and crumbling.
“NEMA has mobilised response agencies and volunteers to an explosion in a building suspected to be loaded with (fireworks) in the Jankara area of Lagos,” agency spokesman Yushau Shuaib said in a statement.
“Search and rescue officers of NEMA (are) having hectic time to reach the place due to traffic and crowds,” he said.
Jankara, home to a large market, is located in the Lagos Island area, among the oldest and most densely packed neighbourhoods in the city.
Fireworks are popular in Nigeria during the Christmas and New Year holidays.
Nigeria is Africa’s most populous nation with some 160 million people, and Lagos is considered the continent’s second-largest city after Cairo.