Twitter Inc. on Thursday said it permanently banned Alex Jones and his website Infowars, effectively taking away one of the last few online microphones available to the right-wing provocateur.

While other tech companies including Apple Inc., Facebook Inc. and Alphabet Inc.’s YouTube previously suspended various accounts associated to Mr. Jones, Twitter had allowed him to remain on its platform. Twitter said Thursday its decision was based on reports of tweets and videos Mr. Jones posted in the past 24 hours “that violate our abusive-behavior policy, in addition to the accounts’ past violations.”

Among his recent posts was one video in which he berated and insulted a CNN reporter.

Twitter last month temporarily suspended Mr. Jones for seven days for violating its content policy.

Mr. Jones frequently touts discredited conspiracy theories, most notably labeling as a hoax the 2012 shooting at Sandy Hook Elementary School that killed 20 children.