Twitter began purging its platform of millions of suspicious or fake accounts Thursday.
Some of Twitter's most prominent users, including President Donald Trump, saw their follower counts decrease by hundreds of thousands of accounts.
"Action on this starts today," Twitter's chief executive and co-founder Jack Dorsey tweeted, adding he lost 200,000 followers.
On Wednesday, Twitter announced that it would begin deleting "locked" accounts, accounts that were deactivated because Twitter deemed them to be suspicious or fraudulent.
Twitter's own official account, @Twitter, was one of the purge's biggest victims. The account lost roughly 10 million followers Thursday, dropping some 12 percent to about 55 million.
Trump lost about 200,000 followers. Former President Barack Obama lost roughly 2.6 million followers. Musician Katy Perry, the most followed account on Twitter, lost about 2.7 million followers in the purge.
In the announcement, Twitter executive Vijaya Gadde said the company estimated the average user would lose four followers or fewer.
"We understand this may be hard for some, but we believe accuracy and transparency make Twitter a more trusted service for public conversation," Gadde said in a statement.
"Though the most significant changes are happening in the next few days, follower counts may continue to change more regularly as part of our ongoing work to proactively identify and challenge problematic accounts."
While the general reaction to the loss of followers was relatively calm, the purge was still controversial on social media. Some conservatives on Twitter argued that the purge was politically motivated.
"Look, if they're genuinely fake or dead accounts, I have no problem with it," tweeted former Republican presidential candidate Herman Cain. "But how do we know?"
Twitter said locked accounts were accounts that were opened by an authentic person but have likely been hacked, according to the company's metrics.
