Facebook CEO Zuckerberg hits back, says whistle-blower’s claims are untrue

An error during routine maintenance on Facebook’s network of data centers caused Monday’s collapse of its global system for more than six hours, leading to a torrent of problems that delayed the repairs, the company said on Tuesday.

The outage was the largest that Downdetector, a web monitoring firm, said it had ever seen. It blocked access to apps for billions of users of Facebook, Instagram and WhatsApp, further intensifying weeks of scrutiny for the nearly $1 trillion company.

At a U.S. Senate hearing on Tuesday, a former employee turned whistleblower accused Facebook of putting profits before people’s safety, which the company denies.