Nigeria(CNN)The death toll in an explosion that rocked the city of Kano in northwest Nigeria has risen to nine, authorities say.

Earlier, Kano's Police Commissioner, Sama'ila Shu'aibu Dikko told CNN that the explosion was from a gas cylinder that went off near a school in the Sabon Gari area of Kano.

"It was a gas explosion. There was a welder around the area and his gas cylinder exploded just very close to a private school... we have recovered four casualties, including the welder and a female. No child was affected," Dikko told CNN from the scene of the blast.

Eyewitnesses told local media that they saw a suicide bomber set off a bomb at the scene of the blast. Unconfirmed videos of the blast circulating Tuesday on social media also show some schoolchildren in bloodied uniforms being taken away from the scene of an explosion.

The local police chief said an unknown number of people were injured but did not expand further on the circumstances that led to the explosion.

Kano's Information Commissioner, Mohammed Garba, also told CNN that no infrastructure of the children's school was hit by the blast.

"The explosion occurred around a shop where animal feeds are being sold. The explosion site is opposite a nursery and primary school.... no building of the school was affected."

The eyewitness accounts of a suicide bomber have led to allegations of a cover up.

Kano police chief, Dikko, however insisted that the incident was a gas cylinder explosion while describing as "mischievous information" the reports of a suicide bombing.

"There is no coverup. We were at the scene with our experts. We recovered a lot of chemicals inside the welding workshop. It was a gas cylinder explosion," the police commissioner told CNN.

Human rights lawyer, Chidi Odinkalu, argued that there hasn't been enough time for authorities to determine the cause of the explosion and that there was no adequate laboratory facility in the state to carry out the analysis just a few hours after the blast.

"Even if they determine that it was a gas explosion, they've got to also rule out that the gas was weaponized for purposes of an attack," he added. "That again, they've not had the time to do. They've not issued any statement saying that the circumstances of the gas explosion did not have any imputation of criminal enterprise. Obviously they could not have done that in the time available."

The use of substandard cooking and welding gas cylinders, as well as direct exposure to flame in densely populated areas have led to previous explosions in the past.

A welding gas cylinder is a common sight in many makeshift welding stores in Nigeria due to its relevance to the craft.

In northwestern Ogun State, at least seven people were killed in different gas explosions that rocked the city last year. State officials blamed some of the explosions on welding gas while announcing a ban on its use.

Tuesday's blast comes weeks after Nigeria's Department of State Services (DSS) warned of a plot by criminal elements to launch bomb attacks "on critical infrastructure and other frequented public places like worship and relaxation centers" across the country.

Source : https://edition.cnn.com/2022/05/17/africa/explosion-kills-four-nigeria-intl/index.html