After facing criticism from those who felt it had enabled the spread of terror-related messaging, Twitter implemented new anti-terrorism policies. With those policies, the social network has suspended 935,897 accounts since 2015. That figure covers accounts that "actively incite or promote violence associated with internationally recognized terrorist organizations, promote internationally recognized terrorist organizations, and accounts attempting to evade prior enforcement."
In the company's most recent Transparency Report, it revealed 300,000 accounts were suspended just in the first half of 2017. 75% were removed before they first tweeted.
Most of those suspensions aren't due to external reporting. such as from governments. Twitter says its own tools were responsible in 95% of cases.