The Federal Trade Commission(FTC) has warned that it will not hesitate to punish companies caught using fake online reviews or other deceptive endorsements to deceive their customers.

The warning follows letters to more than 700 leading companies urging them not to use illegal practices such as fake reviews and others in their online marketing and advertising campaigns.

Companies that received the notification were also asked to distribute the letter to all subsidiaries that sell services and products within US borders.

Illegal actions and practices that could result in penalties include the false assertion of an endorsement by a third party, the misrepresentation that an endorsement represents the experiences, views or opinions of users or alleged users, the use of an endorsement to make misleading claims for benefits, the failure to disclose an unexpected material connection to an endorser and, finally, the misrepresentation that the endorser’s experience.