Twitter on Thursday said it had banned far-right conspiracy theorist Alex Jones from its platform as well as the account of Infowars, the website he operates.
"Today, we permanently suspended @realalexjones and @infowars from Twitter and Periscope," the social network said.
"We took this action based on new reports of Tweets and videos posted yesterday that violate our abusive behavior policy, in addition to the accounts' past violations."
The move came a day after President Donald Trump's administration warned of a possible legal crackdown on big technology companies over political bias, a bombshell announcement that came as social media executives including Twitter's Chief Executive Officer Jack Dorsey were defending their policies before lawmakers.
The hearing was also attended by Jones, who said he came to highlight his deplatforming and "censorship" from other sites including Facebook and YouTube.
He later posted videos showing himself verbally confronting a CNN reporter as well as Republican Senator Marco Rubio in a hallway.
His Infowars website on Thursday suggested the incident involving the journalist, Oliver Darcy, may have been the cause of the ban.
"Watch the encounter that started it all," the site posted above the clip.
- 9/11 and Sandy Hook -
Twitter had previously resisted calls to ban Jones, though it prevented him from posting on his account for a week last month.
Jones is best known for disputing the veracity of the September 11 attacks and the Sandy Hook school massacre, which he has described as an elaborate hoax involving "crisis actors" in a conspiracy involving the administration of former president Barack Obama.
Parents of some of the children killed in the attack are pursuing a defamation case against him. He had almost 900,000 followers on Twitter before he was banned.
- Justice Department probe -
The Justice Department's announcement Wednesday that it would probe Big Tech over competition or political bias appeared to escalate a war between the administration and Silicon Valley after a series of attacks by Trump claiming tech firms were biased against conservatives.
According to the statement, Attorney General Jeff Sessions will convene a meeting of state attorneys general later this month "to discuss a growing concern that these companies may be hurting competition and intentionally stifling the free exchange of ideas on their platforms."
It came at the conclusion of a Senate Intelligence Committee hearing at which Dorsey and Facebook chief operating officer Sheryl Sandberg testified in a largely collegial atmosphere where the executives and senators spoke of the need for further efforts to thwart foreign influence campaigns on social media.