The top US health official on Tuesday issued a stark warning to parents, tech companies and regulators, saying the evidence is growing that social media use may seriously harm children.

In a lengthy advisory, US surgeon general Vivek Murthy said that while not without benefits, "there are ample indicators that social media can also have a profound risk of harm to the mental health and well-being of children and adolescents."

Social media use by young people in the United States is nearly universal, with up to 95 percent of adolescents reporting using a social platform and more than a third saying they do so "almost constantly," according to the Department of Health and Human Services.

Murthy's report said social media can help children and adolescents find a community to connect, but that it also contains "extreme, inappropriate, and harmful content," which can "normalize" self-harm and suicide.

It can perpetuate body dissatisfaction, eating disorders and depression and expose children to online bullying while they are undergoing a critical stage in brain development, the report warned.

Murthy called on policymakers to strengthen safety standards around social media and urged tech companies to responsibly assess the impact of their products on children and share data with researchers.

He also advised parents to establish tech-free zones at home in order to promote in-person communication, and to educate children by modelling healthy, responsible online behavior.

The report comes at a time when authorities across the United States are searching for ways to regulate social media use, and curb its ill-effects on young people in particular.

Earlier this month, the US state of Montana banned the use of TikTok on its territory. The Chinese-owned video sharing giant is challenging the decision in court. And in March, Utah became the first US state to require social media sites to get parental consent for accounts used by minors.

"We are in the middle of a national youth mental health crisis, and I am concerned that social media is an important driver of that crisis -- one that we must urgently address," Murthy said.