A natural gas explosion destroyed an apartment building in Dallas’ Oak Cliff neighborhood, killing three people, including a child, and injuring several others.

Fire officials said crews responded to a gas leak before a fire broke out, which quickly escalated into a major multi-alarm emergency.

At least 23 people were believed to have lived in the building, with some still unaccounted for as rescue teams searched the debris.

Authorities confirmed the blast was caused by natural gas, and the National Transportation Safety Board is investigating the incident, NBC 5 News has reported.

Early reports suggest a contractor may have accidentally struck a gas line during work at the site.