An explosion has ripped through a warehouse where witnesses say fireworks were stored in Nigeria's largest city, sparking a fire.

The explosion happened around 9 a.m. Wednesday on Lagos Island in Lagos, shaking windows of homes miles away. A thick cloud of smoke could be seen rising over the island. The fire quickly spread over two blocks. Two firemen showed up ina fire truck and local residents grabbed fire hoses to try to help put out the flames.

It was not immediately clear if there were any casualties. An hour after the explosion fireworks were still going off. Witnesses say the building had firework inside.