Twitter says it suspended more than 375,000 accounts for violations linked to the promotion of terrorism in the last six months of 2016.
The social network used its latest transparency report to reveal that since August 2015 more than 636,000 Twitter accounts had been shut down because of links to extremism.
The micro-blogging site also said the majority of those shut down had been found by the firm's own spam account scanning technology.
Between July 1 and December 31 2016, a total of 376,890 accounts were suspended.
Last week, MPs accused Twitter, along with Facebook and Google, of not doing enough to tackle hate crime and extremism online.
The companies were told by the Home Affairs Select Committee they had a "terrible reputation" for acting on offensive material posted online.
Twitter's Jeremy Kessel said the new report, which is the company's 10th to be released in the last five years, was an important part of modern society.
"A lot has changed over the past five years, both at Twitter and around the world," he said.
"But the need for transparency into government and company actions has never been more important given the current climate of continued crackdowns on freedom of expression and limitations on citizens rights around the globe.
"We're more committed than ever to improve our approach and to give the world more meaningful insights and data to better understand the complex global issues we face every day. Transparency will always be part of our DNA and we welcome your feedback."