Two days after the European Union hit X with a major fine, the social media platform has deleted an advertising account used by the European Commission, as owner Elon Musk compared the bloc to Nazi Germany.

"Your ad account has been terminated," X’s head of product, Nikita Bier, wrote on Sunday in a reply to the European Commission’s post on X announcing its €120 million ($140 million) fine for breaking transparency rules.

Bier said the EU account created a post that "deceives users into thinking it’s a video and to artificially increase its reach." The European Commission’s X account and its posts remain visible, however.

Tech billionaire Musk meanwhile continued to share his hostility towards the "tyrannical, unelected bureaucracy oppressing the people of Europe" on Sunday.

Musk reposted a user’s comment that the EU was "The Fourth Reich", along with a picture of the EU flag peeling off to reveal a Nazi Germany flag with a swastika beneath.

The EU announced its fine on Friday, accusing the platform of misleadingly authenticating user accounts with blue ticks, withholding data from researchers and not transparently documenting advertisements placed on the platform.

The commission said the amount of the fine was proportionate to the infringement. Musk responded on X with a call to "abolish" the EU.

The fine also drew criticism from US Secretary of State Marco Rubio, who called the fine "an attack on all American tech platforms and the American people."