The U.S. military says coalition forces have discovered a suspected insurgent chemical production facility and storage site in northern Iraq.

A senior military official says the chemicals collected at the site in Mosul are being analyzed to determine the type and quantity produced.

But another official close to the investigation told VOA's Baghdad correspondent that the materials are "precursor chemicals commonly associated with the production of narcotics."

In a statement earlier Saturday, the military said the raid, conducted Tuesday, was based on intelligence obtained during interrogation of detainees. An investigation is continuing to determine which terrorist or insurgent group built and operated the covert facility.