A former security chief for Twitter has turned whistleblower and testified that the company misled users and US regulators about gaps in its security.
Peiter Zatko also claimed that Twitter underestimated how many fake and spam accounts are on its platform.
The accusations could affect a legal battle between Twitter and billionaire Elon Musk, who is trying to cancel his $44bn (£37bn) deal to buy the company.
Twitter says Zatko’s allegations are inaccurate and inconsistent.
It says he was sacked in January for ineffective leadership and poor performance.
In Zatko’s damning revelations, he accused Twitter of failing to maintain stringent security practices and “lying about bots to Elon Musk”.
Twitter has faced a number of high-profile hacks with Barack Obama, Joe Biden, and Kanye West all targeted.
Among his concerns, Zatko alleges that Twitter suffered from a usually high rate of security incidents – “approximately one security incident each week serious enough that Twitter was required to report it to regulators”.
He said that so-called insider threats – security risks posed by people with malicious intent from within the company – went “virtually unmonitored”.
The former security chief revealed his concern about how Twitter handled data, alleging that too many employees had access to sensitive systems and user data.