The social network says the suspensions are primarily related to Islamic State
Twitter has suspended more than 125,000 accounts for threatening or promoting terrorist acts - most related to Islamic State.
The accounts have been shut down over the past eight months as social media firms respond to pressure from the US government for them to be more proactive.
Twitter has been using spam-fighting technology to seek out accounts.
Islamic State is known to use social media to radicalise and lure recruits, prompting Twitter to "significantly" increase the size of its reviewing team.
The company said it had already had seen "an increase in account suspensions and this type of activity shifting off of Twitter".
But it added there was no "magic algorithm" for identifying terrorist content.
"Like most people around the world, we are horrified by the atrocities perpetrated by extremist groups," Twitter said in a statement.
"We condemn the use of Twitter to promote terrorism."
The company says they are "an open platform for expression", explaining that they "have always sought to strike a balance between the enforcement of our own Twitter Rules covering prohibited behaviors, the legitimate needs of law enforcement, and the ability of users to share their views freely – including views that some people may disagree with or find offensive".
The statement added that the company would continue to "engage with authorities and other relevant organisations to find solutions to this critical issue and promote powerful counter-speech narratives".
Child pornography had previously been the only abuse that was automatically flagged by technology for human review.
Separately, reports suggest that Twitter is set to introduce an algorithmic timeline in the coming days or weeks.
Buzzfeed News says the algorithm will show tweets it "thinks people most want to see".
The move would be a major departure from Twitter's traditional chronological timeline, and the prospect has already been criticised by users of the social network.