WASHINGTON (REUTERS) - The US Senate will hold an Oct 26 hearing with tech firms TikTok, Snap's Snapchat and Alphabet's YouTube about their platforms' impact on young users, the panel said on Tuesday (Oct 19).

"Recent revelations about harm to kids online show that Big Tech is facing its Big Tobacco moment - a moment of reckoning," said Senator Richard Blumenthal, who chairs the Senate Commerce consumer protection subcommittee holding the hearing.

"We need to understand the impact of popular platforms like Snapchat, TikTok and YouTube on children and what companies can do better to keep them safe."

Senator Marsha Blackburn, the top Republican on the subcommittee, said: "TikTok, Snapchat and YouTube all play a leading role in exposing children to harmful content."

A Snap spokesman said the company looks forward to discussing its "approach to protecting the safety, privacy and well-being" of the Snapchat community.

TikTok confirmed it would take part, while YouTube did not immediately respond to a request for comment.

Earlier this month, the panel held a hearing with Facebook whistle-blower Frances Haugen, who turned over thousands of documents she said showed the company had failed to protect young users.

"The company's leadership knows how to make Facebook and Instagram safer, but won't make the necessary changes because they have put their astronomical profits before people.

Congressional action is needed," Ms Haugen said.

At the hearing, Ms Blackburn accused Facebook of turning a blind eye to children aged below 13 on its services.

"It is clear that Facebook prioritises profit over the well-being of children and all users," she said.

Facebook chief executive Mark Zuckerberg rejected the criticism.

"The argument that we deliberately push content that makes people angry for profit is deeply illogical," he wrote.

Last month, Facebook said it was putting on hold a new version of its Instagram photo-sharing app for kids.