The House committee probing potential national security threats from China wants the Federal Trade Commission to investigate whether TikTok violated child privacy laws when it launched a last-ditch lobbying blitz to defeat the bill requiring ByteDance, TikTok’s owner, to divest it.

TikTok pushed a message calling for users to contact their Members of Congress, and urge them to vote against the Protecting Americans from Foreign Adversary Controlled Applications Act, which is now law.

Rep. John Moolenaar, chairman of the China panel, and Raja Krishnamoorthi, ranking member, want the FTC to probe whether TikTok sent pop-up messages to children under the age of 13 in violation of the Children’s Online Privacy Protection Act.

“We are gravely concerned that an app controlled by the Chinese Communist Party appears to have the unfettered ability to manipulate the American public, including America’s children,” they wrote in a letter to FTC chair Lina Khan.

They noted reports that TikTok’s message impacted young children in classrooms, and in one instance, a child called a Congressional office and threatened to commit suicide in response to the false message that the app was going to be banned.

TikTok would only be banned in the US in the event that ByteDance doesn’t unload it over the next nine months.

The China panel is called the House Select Committee on the Strategic Competition Between the US and the Chinese Communist Party.