The head of the Federal Communications Commission is going on the offensive against tech companies in an effort to make his case for repealing net neutrality rules.

FCC chairman Ajit Pai on Tuesday accused Twitter (TWTR) and other tech companies of being disingenuous by arguing for a free and open internet while they "routinely block or discriminate against content they don't like."

The remarks came as part of a speech on his recently revealed plan to unravel Obama-era net neutrality protections at a telecom policy event in Washington DC. The 2015 rules were intended to keep the internet open and fair by preventing broadband providers from playing favorites with online content.

Pai argued that it's actually the "edge providers," the FCC's term for services like Google (GOOGL) and Facebook (FB), that "are a much bigger actual threat to an open Internet than broadband providers, especially when it comes to discrimination on the basis of viewpoint."

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Pai, a Republican commissioner appointed to head the agency by President Trump, specifically called out Twitter for appearing to have a "double standard when it comes to suspending or de-verifying conservative users' accounts as opposed to those of liberal users.

He did not specify which conservative accounts he was referring to. Twitter recently removed the verification from several prominent users, including controversial conservative commentator Laura Loomer and white nationalists like Richard Spencer and Jason Kessler.

Pai also criticized Twitter for briefly blocking a campaign ad from Rep. Marsha Blackburn, a Republican representing Tennessee.

"When it comes to a free and open internet, Twitter is part of the problem," Pai said.

A spokesperson for Twitter said the ad was not censored. "Anyone voluntarily following her account could see it, as is their choice as a consumer when they choose to follow her," the spokesperson said. "Because advertisements are served to users who do not necessarily follow an account, we therefore have higher standards for their content."

Pai's decision to seek a full repeal of the rules was praised by the telecommunications trade groups as a boon for broadband investment, but loudly panned by the tech industry and consumer advocacy groups.

In his speech, Pai didn't just attack tech companies. He also went after celebrities like musician Cher and actors George Takei, Mark Ruffalo and Alyssa Milano by name for criticizing the rules.

"These comments are absurd," Pai said after reading off a tweet from Ruffalo claiming the net neutrality repeal would be fuel for authoritarianism. "Getting rid of government authority over the Internet is the exact opposite of authoritarianism."