The Elon Musk-owned social media platform has delivered on its promise to remove blue verification checks from accounts that don't pay a monthly fee to keep them.

The blue checks disappeared on Thursday from the accounts of some of the most followed celebrities and public figures on Twitter, including Pope Francis, Beyonce, Oprah Winfrey, Donald Trump and Lady Gaga.

The purge comes after owner Elon Musk introduced a new paid service last year called Twitter Blue with the intention to "democratize journalism and empower the voice of the people."

Around 300,000 users had the blue check mark before Musk pulled the plug on the verification system on Thursday. The symbol helped to distinguish the profiles of public figures from impostor accounts and provided an extra shield to prevent misinformation.

Some users, including author Stephen King, appear to have kept the blue check but denied paying for the new service.

Musk replied to King's tweet with "You're welcome namaste", and confirmed in another tweet that he's "paying for a few [accounts] personally."

Why Twitter Blue?

Twitter began tagging users with a blue check mark about 14 years ago. After buying the social media giant Twitter for $44 billion (€40.1 billion) last October, Musk has been trying to increase the platform's revenue by offering subscription and premium services.

Musk has previously claimed that the system that previously assigned the check marks was "corrupt and nonsensical."

Multiple impostor accounts, including some impersonating Musk's Tesla and SpaceX, popped up shortly after the introduction of Twitter Blue. Twitter temporarily suspended the service days after launch.

The costs to display the verified check mark under the new service vary — individual users can pay $8 per month, but organizations have a starting price of $1,000 per month to keep the symbol.

The Thursday purge has also hit politicians and official bodies, with some concerned about the public not knowing which Twitter accounts that inform about natural disasters are real.

"There really ought to be a way for emergency managers to verify that they are real on this website or imposters will cause suffering and death," tweeted US Senator Brian Schatz.

Only 116,000 accounts have signed up to Twitter Blue last month, according to the digital intelligence platform Similarweb.