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MIAMI (CBSMiami) – A consumer watchdog is urging the Federal Trade Commission to crack down on deceptive social media ads.

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The group, Truth in Advertising, says many social media stars fail to disclose when they are being paid to push products and services.

It unearthed more than 100 Instagram posts by the Kardashian and Jenner sisters that it says ignored the law, because they were not clearly labeled as ads.

Pop star Selena Gomez has the most popular Instagram post ever. It’s a photo of her sipping from a Coca-Cola bottle, and it has more than 5 million likes.

Olympian Usain Bolt has plugged Gatorade.

Lady Gaga gushed about her Dior jeans.

Truth in Advertising alleges these posts were not labeled as ads – and that may be a problem.

“There’s restrictions on commercial speech,” said Truth in Advertising Executive Director Bonnie Patten. “So if they are getting things for free or are getting paid to post what they’re photographing… then there are rules and regulations.”

The FTC issued an enforcement policy statement in December which said consumers must be told in a “clear and conspicuous” way when a social media post is paid for. The posts should include hashtags such as #ad or #sponsored.

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Earlier this month, Truth in Advertising, accused the Kardashian-Jenner sisters of not disclosing relationships with companies they are promoting to their more than 300 million combined Instagram followers.

“These are business women who are experts at marketing,” Patten said. “That was one of the reasons that we decided to focus on them.”

The reality TV stars responded by amending several posts.

Kylie Jenner noted her rental of a mansion, featured in some of her posts, was actually a birthday gift from Airbnb.

Social media sites handle paid ads differently.

YouTube tells users they are responsible for following any applicable laws.

Snapchat requires a disclaimer identifying the advertising.

Instagram encourages users to follow industry best practices around transparency.

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Facebook says it has added a new tool for tagging branded content.