The FCC is speaking out against cell phone jammers and reminding consumers they are illegal.

The agency cited recent reports of some commuters on trains and buses using cell phone jammers to block the conversations of fellow riders.

The FCC says it has a zero tolerance policy in this area and will take aggressive action against violators.

Marketing, selling or operating these devices is punishable by a fine of up to $16,000 per violation, seizure of the equipment, and possible prison time.