MONTGOMERY COUNTY, Md. (WDVM) – Residents of an apartment building in Maryland were injured on Wednesday morning after a portion of the building exploded and caught fire, officials said.

Approximately 100 firefighters were dispatched to the Potomac Oaks Condominiums in Gaithersburg following reports of the explosion and injuries.

A significant portion of the building caught fire after the explosion. At least two apartments partially collapsed, as seen in photos from the scene.

Montgomery County Fire and Rescue Service Chief Scott Goldstein delivered an update shortly after the incident, confirming that 12 people were injured. Ten of those were hospitalized, two with critical injuries. The victims also included four children.

At the time, there was still an active gas-fed fire in the basement of the building Goldstein said.

Nine apartments were compromised as a result of the explosion and fire. It wasn’t clear how many people, in total, would be impacted.

Washington Gas was working to shut off the gas that was feeding the fire on Wednesday morning.