Twitter Inc. banned some kinds of automated accounts and placed restrictions on posting simultaneously from multiple accounts, curbs that drew complaints Wednesday from conservative members who claim they are being unfairly targeted by the company.
Twitter updated its rules to prohibit users who operate multiple accounts from simultaneously tweeting, retweeting, liking posts and following accounts—a practice common among bot operators trying to coordinate activity across legions of accounts.
Social-media companies including Twitter have faced criticism over their efforts to prevent bullying and abusive content. The companies have tried to rein in such actions while at the same time avoiding the perception they censor unpopular opinions. Twitter in particular is focusing on cracking down on spam as a way to reduce the amount of fake news on its site.
Twitter’s actions caused an uproar among some right-wing activists. The hashtag #TwitterLockout began trending, driven mainly by users expressing dissatisfaction over their shrinking number of followers.
“Let’s get loud,” a post on the Twitter account of radio host John Cardillo said. “This is happening to all of us. Every conservative verified account I know, including me.”
A spokeswoman declined to say how many accounts Twitter suspended. She said the company enforces its rules without political bias. Some accounts, for example, could return to Twitter if their owners provide a phone number to verify that they are operated by humans, she said.
The tumult Wednesday came a day after a prominent white nationalist sued Twitter for kicking him off the social network, the latest in a spate of legal attacks by members of the far-right claiming tech companies discriminate against their viewpoints and challenging the idea that they operate neutral platforms.
The suit by Jared Taylor, filed Tuesday in state Superior Court in San Francisco, argues that Twitter violated California law protecting free speech in public spaces when it banned Mr. Taylor in December. Twitter told Mr. Taylor by email that it did so under a rule in its user agreement that bars accounts affiliated with organizations that promote violence, according to the suit. Mr. Taylor says he neither advocated violence nor was affiliated with such groups.
Twitter declined to comment on Mr. Taylor’s case. It added the rule cited in Mr. Taylor’s suit in December as part of a broader effort to reduce “hateful and abusive” content.
Mr. Taylor’s suit follows others by right-wing groups and individuals in recent months claiming they were treated unfairly by tech companies, including Twitter and YouTube, an arm of Alphabet Inc.’s Google.
In January, Charles Johnson, an investor and conservative activist, sued Twitter in state Superior Court in Fresno, Calif., for banning him, claiming it was inconsistent in applying its rules. Twitter kicked off Mr. Johnson in 2015 after he sent a tweet offering to “take out” civil-rights activist DeRay Mckesson. Mr. Johnson says he was referring to investigating Mr. Mckesson.
In October, Prager University, a nonprofit institution that produces short videos from conservative perspectives, sued YouTube and its parent, Google, in federal court, claiming the tech giant illegally censored some of its content as part of a wider effort to silence conservative voices.
Those cases are pending.
Twitter and Google, along with Facebook Inc., also have come under pressure in recent years from users who say the platforms don’t do enough to prevent disturbing content including threats against other users, revenge porn and hate speech.
In response, they have broadened rules preventing certain kinds of hate speech, particularly that targeting other users.
Twitter’s rules say it believes in freedom of expression “but that means little as an underlying philosophy if voices are silenced because people are afraid to speak up.”
The companies also now are navigating new European rules that require them to proactively remove hate speech on their sites.
“These are hard issues,” said Danielle Citron, a University of Maryland law professor, who advises tech companies, including Twitter, on how to protect against abuse without impeding free speech. “Coming to a global consensus on these issues is not impossible, but it’s going to be challenging.”
Noah Peters, the Washington-based attorney representing Mr. Taylor, said his suit doesn’t take issue with Twitter’s need to kick off users who harass others, but he says Mr. Taylor didn’t harass users on Twitter.
Mr. Peters pointed to what he says is precedent in California that privately owned spaces can constitute public forums, and arguing that because Twitter is a public forum, it can’t discriminate against certain views. The California public-space ruling hasn’t previously been applied to the internet, Mr. Peters said.
“What we’re talking about is power—who has the power to shape the debate,” Mr. Peters said. “Is this going to be a thing where Twitter gets to determine who wins the debate?”
Write to Georgia Wells at Georgia.Wells@wsj.com