Twitter says it was the victim of a “coordinated social engineering attack” by unspecified individuals who targeted Twitter employees with access to sensitive internal administrative systems.

The breach implicated the accounts of some of the richest and most famous people on the social media platform, including Jeff Bezos, Elon Musk, Bill Gates, former President Barack Obama, Joe Biden, Kanye West and others.

As Twitter investigates what appears to be the largest and most coordinated hack in Twitter’s history, the company has vowed to examine what “other malicious activity” the hackers may have committed.

“Internally, we’ve taken significant steps to limit access to internal systems and tools while our investigation is ongoing”, - Twitter said in a series of tweets.