Facebook exec grilled over kids' app

US lawmakers have betrayed their growing frustration with Facebook. Senators have accused executives of hiding their own research about the harmful effects of social media on children.

Facebook's Global Head of Safety, Antigone Davis, testified before a Senate committee. Senators grilled her over the company's photo and video sharing service, Instagram.

Executives had been developing Instagram Kids, a service tailored to children 13 and under. Earlier this week, they suspended development of the platform. Still, senators accused them of knowing that Instagram caused mental and emotional harm.

Davis said children under 13 are banned from using the service. She said the company deleted more than 600,000 accounts from June to August. But many children use it by lying about their age.

The senators have invited a whistleblower who shared internal company research to testify next week.