California police on Thursday said a small plane crashed into a commercial building, killing at least two people and injuring 18 others

In a post on X, the police said that the crash took place early in the afternoon near Fullerton Municipal Airport, 25 miles (40 kilometres) southeast of Los Angeles but the cause remains unknown.

Also, 10 people were hospitalized and eight others were treated at the scene.

According to the police, investigators do not yet know if the deceased were plane passengers or if they were workers at the building where it crashed.

Television footage showed a gaping hole in the roof of the building, with smoke pouring out.

“All we hear is like a loud noise, boom, and that’s it. Then we started running out of the building,” Jerome Cruz, one of the workers who witnessed the scene, told CBS News.

According to the Federal Aviation Administration, which has opened an investigation, the plane was a single-engine Van’s RV-10, a small model with four seats.

Two dead, 18 injured in California small plane crash