Mark Zuckerberg has dismissed attacks on Facebook as “misrepresenting” the work the company does after a whistleblower told the US Congress the site harms children’s mental health and fuels polarisation.

Sharing a memo he sent to staff on his personal Facebook page, the social network’s founder said the company “cares deeply about issues like safety, well-being and mental health”.

It came in response to Frances Haugen, a former Facebook data scientist turned whistleblower, who told the US Senate Commerce Subcommittee on Consumer Protection on Tuesday that Facebook refuses to change its products because executives elevate profits over safety.

Ms Haugen accused the tech giant of being aware of the apparent harm Instagram could have on some teenagers and their body image, and said the firm had been dishonest in its public fight against hate content and misinformation by hiding research that shows it amplifies such content.

She has come forward with thousands of pages of internal research documents she secretly copied before leaving her job in the company’s civic integrity unit.

Mr Zuckerberg hit back, saying Ms Haugen’s testimony and the recent coverage of the company linked to it “just doesn’t reflect the company we know” and it was “difficult to see coverage that misrepresents our work and our motives”.

“At the most basic level, I think most of us just don’t recognise the false picture of the company that is being painted,” he said.

“At the heart of these accusations is this idea that we prioritise profit over safety and well-being. That’s just not true.

“For example, one move that has been called into question is when we introduced the Meaningful Social Interactions change to News Feed.

“This change showed fewer viral videos and more content from friends and family – which we did knowing it would mean people spent less time on Facebook, but that research suggested it was the right thing for people’s well-being. Is that something a company focused on profits over people would do?”

Mr Zuckerberg also accused Facebook’s critics of scaring other companies out of doing research on their global impact.

“We have an industry-leading research programme so that we can identify important issues and work on them. It’s disheartening to see that work taken out of context and used to construct a false narrative that we don’t care,” he said.

“If we attack organisations making an effort to study their impact on the world, we’re effectively sending the message that it’s safer not to look at all, in case you find something that could be held against you.”

In what has been a difficult week for the social network, Mr Zuckerberg also commented on the major outage which hit the company on Monday, taking Facebook, Instagram and WhatsApp offline for more than five hours.

He described it as “the worst outage we’ve had in years” and said staff had “spent the past 24 hours debriefing how we can strengthen our systems against this kind of failure”, but did not offer an further insight into what had caused the issue.

Facebook had said the incident was caused by a “faulty configuration change” within its network infrastructure.