YouTube has been fined a record $170m (£139m) by a US regulator for violating children's privacy laws.
Google, which owns YouTube, agreed to pay the sum in a settlement with the Federal Trade Commission (FTC).
The video-streaming site had been accused of collecting data on children under 13, without parental consent.
The FTC said the data was used to target ads to the children, which contravened the 1998 Children's Online Privacy Protection Act (Coppa).
"There's no excuse for YouTube's violations of the law," said FTC Chairman Joe Simons.
He added that when it came to complying with Coppa, Google had refused to acknowledge that parts of its main YouTube service were directed at children.
However, in presentations to business clients, the company is accused of painting a different picture.
YouTube also regularly reviewed content for inclusion in its separate YouTube Kids app.
Google will have to pay $136m to the FTC - the largest ever fine in a Coppa case - and a further $34m to the state of New York.
As part of Google's settlement with the FTC, the company will be required to create a new system so that content directed at children will be clearly labelled. (BBC)