The NFL says it is looking into a report that the San Diego Chargers used a banned sticky substance during Monday night's loss to the Denver Broncos.

FoxSports.com reported Sunday that during Monday night's game, an equipment manager came onto the field with an illegal substance on hand towels. The website says one of the officials, Jeff Bergman, saw the towels and tried to confiscate the substance. When the equipment manager wouldn't give it up, the officials made him empty his pockets and found a skin colored or clear type of tape.