Abuja, Nigeria — Police in Nigeria's Kano state say four people have died following an explosion near a school Tuesday morning.

The victims include three males and one female, according to a statement Tuesday by the Kano state police command. Many people were injured, including young school children.

Police commissioner Samaila Shuaibu visited the scene in the Sabon Gari area of Kano state and said a rescue mission was underway. He said the loud explosion was not a bombing as initially speculated.

Shuaibu said analysis revealed the explosion was caused by a gas cylinder in a welder's shop, near a nursery and primary school where students were in the day's classes.

The explosion caused the welder's shop to collapse and trapped many people. VOA's Hausa service reporter Baraka Bashir visited the site.

"At the place the gas cylinder was, there were chemicals, there were a lot of chemicals in his shop, when the cylinder exploded, the chemicals caught fire," Bashir said

Meanwhile, local news organizations report security officials fired gunshots into the air to disperse a restless crowd at the scene of the explosion.

Authorities say a more detailed report on the incident will be released to the public.