Twitter says it will no longer allow people to post identical messages from multiple accounts, cracking down on a tactic that Russian agents and others have allegedly used to make tweets or topics go viral.
The San Francisco-based social network also said it would not allow people to use software to simultaneously perform other actions such as liking or retweeting from multiple accounts.
Twitter, known for freewheeling discussions in short messages, is under pressure from users and Western governments to stem the spread of false news and foreign propaganda, often done with the help of automated accounts known as bots.
Twitter bots disseminated propaganda before the 2016 US elections and have continued to inflame US politics under cover of anonymity, academic researchers and US authorities said.
High-profile alt-right firebrand and white supremacist Richard Spencer called it a "purge", and other right-wing and conservative users of the site have complained of losing thousands of followers overnight.
On Friday, the office of US Special Counsel Robert Mueller charged 13 Russians and three Russian companies, including St. Petersburg-based Internet Research Agency known for trolling on social media.
- Russians charged with US election interference
- Trump blames FBI's Florida failings on Russia investigation
The court document said those accused "had a strategic goal to sow discord in the US political system, including the 2016 US presidential election".
Twitter's new restrictions were aimed at improving "information quality," Yoel Roth of the company's policy team said.
"These changes are an important step in ensuring we stay ahead of malicious activity targeting the crucial conversations taking place on Twitter - including elections in the United States and around the world," Roth said in a statement.
Posting identical messages to multiple accounts, or simultaneously retweeting or liking a message from multiple accounts, could help vault something into Twitter's trending list, giving a false impression of how viral it is among real people.
Twitter said it would give users until March 23 to comply before suspending accounts. It made an exception for bots of broad interest such as earthquake alerts.
Twitter also cracked down on other violations of its terms of service, including fake accounts by people inflating their following. But it seems some real people have been caught up in the changes.
"I've definitely been locked out and unfairly targeted because I'm a Trump supporter who also tweets out Bible verses," Twitter user @ThankUGOD4Trump told tech site Gizmodo. Gizmodo suggested she may have been temporarily banned after retweeting a video claiming the classmates of the Florida school shooting victims were paid actors.
In a statement, Twitter said it was "apolitical" and enforces its rules "without political bias".
"As part of our ongoing work in safety, we identify suspicious account behaviors that indicate automated activity or violations of our policies around having multiple accounts, or abuse.
"We also take action on any accounts we find that violate our terms of service, including asking account owners to confirm a phone number so we can confirm a human is behind it. That's why some people may be experiencing suspensions or locks."
Tech site Endgadget noted last month's Twitter cleanout of around 1 million accounts followed a New York Times report on a company which sold fake followers, and this one appears to be in response to the indictments in the ongoing investigation into alleged Russian interference in US domestic politics.
Conservative users opposed to the cleanup are using the hashtag #TwitterLockout.
Reuters / Newshub.