Firefighters in Southern California battle paper products warehouse fire

ONTARIO, Calif. (NBC, KYMA) - Firefighters are battling a major fire at a paper products warehouse in Ontario, California Tuesday morning.

The fire quickly spread inside the massive 1.2 million square-foot building, forcing firefighters to retreat to a defensive posture outside as the building became fully involved.

About 140 firefighters responded to the scene.

No injuries or fatalities have been reported, and the cause of the fire is not yet known.

However, fire officials said the fire was first reported as suspicious, and a person of interest was identified and taken into custody by police for questioning, but no other information is available.

The investigation into the fire is ongoing.