WASHINGTON, June 17 (Reuters) - U.S. Surgeon General Vivek Murthy on Monday called for a warning label to be added to social media apps as a reminder that those platforms have caused harm to young people, especially adolescents.

In an op-ed in the New York Times, Murthy wrote that a warning label alone will not make social media safe for young people but that it can increase awareness and change behavior as shown in evidence from tobacco studies. The U.S. Congress would need to pass legislation requiring such a warning label.

Youth advocates and lawmakers have long accused social media platforms like Facebook, Instagram, TikTok and Snapchat of what they say is a harmful effect on kids, including shortened attention spans, promoting negative body images, and making them vulnerable to online bullies and predators.

"It is time to require a surgeon general's warning label on social media platforms, stating that social media is associated with significant mental health harms for adolescents," Murthy wrote on Monday.

TikTok, Snap and Meta Platforms, owner of Facebook and Instagram, did not respond to requests for comment.

The CEOs of those three companies, along with social media platform X and messaging app Discord, were grilled by U.S. senators in January during a

hearing about online child safety

, with Republican Senator Lindsay Graham accusing the leaders of having "blood on your hands," for failing to protect young users from sexual predators.

Some U.S. states have been working to pass legislation to safeguard children from the harmful effects of social media, such as anxiety, depression and other mental illnesses as a result.

New York state lawmakers this month passed legislation to bar social media platforms from exposing "addictive" algorithmic content to users under age 18 without parental consent.

In March, Florida Governor Ron DeSantis signed a bill that bans children under 14 from social media platforms and requires 14- and 15-year-olds to get parental consent.

(Reporting by Kanishka Singh in Washington and Sheila Dang in Austin; Editing by Tomasz Janowski and Stephen Coates)