CNN  —  The Federal Communications Commission is investigating Amazon and other retailers over the alleged marketing and sale of wireless signal jammers, the agency said Wednesday. Wireless devices that intentionally block or disrupt signals sent by other legitimate electronics, such as cellphones and GPS units, are illegal to both use and sell or advertise to US consumers. In a rare statement publicly confirming the probe, FCC spokesperson Will Wiquist said the FCC has “several ongoing investigations into retailers, including Amazon, for potential violations of Commission rules related to the marketing and sale of equipment without proper FCC authorization.” Wiquist did not specify what other retailers are involved in the probe. The investigation was first reported by NBC News following its earlier reporting on the apparent availability of signal jammers on Amazon’s marketplace. Amazon didn’t immediately respond to a request for comment.