WASHINGTON (Reuters) - The chairman of the Federal Communications Commission, Ajit Pai, accused social media company Twitter Inc TWTR.N of being politically biased on Tuesday as he defended his plan to roll back rules intended to ensure a free and open internet.

Ajit Pai, Chairman of the Federal Communications Commission, testifies before a Senate Appropriations Financial Services and General Government Subcommittee on Capitol Hill in Washington, U.S., June 20, 2017. REUTERS/Aaron P. Bernstein

Pai, a Republican named by President Donald Trump to head up the FCC, unveiled plans last week to scrap the 2015 landmark net neutrality rules, moving to give broadband service providers sweeping power over what content consumers can access.

“When it comes to an open internet, Twitter is part of the problem,” Pai said. “The company has a viewpoint and uses that viewpoint to discriminate.”

He pointed to Twitter’s refusal to let Representative Marsha Blackburn, a Republican, advertise a campaign video with an anti-abortion message.

“To say the least, the company appears to have a double standard when it comes to suspending or de-verifying conservative users’ accounts as opposed to those of liberal users,” Pai said.

A spokesperson for Twitter said that at no time was Blackburn’s video censored and that her followers would have been able to still see it.

“Because advertisements are served to users who do not necessarily follow an account, we therefore have higher standards for their content,” the Twitter spokesperson said.

Twitter in October declined a campaign video advertisement by Blackburn, who announced she is running for the U.S. Senate, saying that a remark by Blackburn about opposing abortion was inflammatory. Twitter later reversed its decision.

Pai's criticism came a day after Twitter and a number of other internet-based companies - including AirBnb, Reddit, Shutterstock, Inc, Tumblr and Etsy ETSY.O - sent a letter urging the FCC to maintain the net neutrality rules.

Trump is a prolific user of Twitter, often posting his unvarnished thoughts on the news of the day. He used Twitter throughout his presidential campaign to circumvent traditional media and talk directly to voters.

Pai has also been a frequent user of the website - acknowledging during the speech, “I love Twitter” - to push his case in favor of the rule changes. On Tuesday afternoon, he even posted a link to his remarks critical of Twitter on his own Twitter account.

Following Pai’s remarks on Tuesday, at an event organized by the libertarian-leaning R Street Institute, two other FCC commissioners said they would support his proposal when they vote on Dec. 14.

The proposed rollback of net neutrality has been seen as a victory for big internet service providers such as AT&T Inc T.N, Comcast Corp CMCSA.O and Verizon Communications Inc VZ.N, which favored a repeal. On the other side, websites such as Facebook FB.O and Alphabet Inc's GOOGL.O Google have favored the rules.

The rules prohibit broadband providers from giving or selling access to speedy internet, essentially a “fast lane,” to certain internet services over others.

“So when you get past the wild accusations, fear mongering and hysteria, here’s the boring bottom line,” Pai said. “The plan to restore internet freedom would return us to the light touch, market-based approach under which the internet thrived.”