LAGOS, Nigeria (AP) — A massive explosion ripped through a warehouse full of fireworks in Nigeria’s largest city on Wednesday, sparking a fire that threatened surrounding city blocks and sending a plume of thick smoke high into the sky. At least one person died and 15 others were wounded, emergency officials said.

The blast occurred around 9 a.m. in the Jankara area of Lagos Island, a neighborhood of narrow streets and tall cement buildings holding shops and housing people sometimes a dozen to a room in the megacity of Lagos. The force of the explosion echoed miles away and shook windows.

An Associated Press journalist saw members of the Nigerian Red Cross treating people with minor cuts and bruises a few blocks from the site. Later, rescuers pulled out a badly charred corpse from the still-smoldering structure.

Many people were injured when they stampeded through the area’s narrow alleyways, said Yushau Shuaib, a spokesman for Nigeria’s National Emergency Management Agency.

“The explosion was not suspected to be a deliberate attack to cause confusion as security agencies have commenced their investigations,” Shuaib said in a statement later Wednesday.

Casualties, however, could rise as rescuers continue to clear debris from the fire. Smoke still rose over the neighborhood as the sun started to set Wednesday over Lagos.

Rubble-strewn streets surrounding the burning buildings were covered in the spent shells of fireworks. Several police officers and security officials found large, mortar-like fireworks in the building, the kind wired to explode as part of a large arrangement put on by professionals.

Nigerians commonly shoot off fireworks and firecrackers to mark Christmas and the New Year, with hawkers roaming in traffic with fistfuls of the small explosives to sell to passing drivers.

Local government officials have tried to ban fireworks this year, in part due to safety and in part due to the fear they can cause in a nation where a radical Islamist sect is carrying out shootings and car bombings. Nevertheless fireworks have exploded across the country in recent days to mark the holiday season.

Immediately after the blast Wednesday, thousands quickly filled the streets surrounding the burning buildings. Others ran away as fireworks continued to explode inside. A half-dozen firefighters arrived at the scene with two trucks and locals also ran fire hoses from the trucks to nearby buildings to try to beat back the flames.

The trucks quickly ran out of water. One man even scooped up water from a puddle with a bowl in an attempt to fight the blaze. One firefighter briefly fought with a young man who took his firefighting helmet off his head and ran away into the swarming crowd. The firefighter shrugged and went back to his truck as the building continued to burn.