X has blocked the European Commission from advertising on its platform, days after the EU fined the social media company €120m (£105m) over concerns surrounding its blue tick badges.

Nikita Bier, who has a senior role at the platform, accused the European Union regulator of attempting to “take advantage” of what he described as “an exploit” in X’s advertising system to promote its announcement of the penalty issued on Friday.

“It seems you believe that the rules should not apply to your account,” he said. “Your ad account has been terminated.”

The irony of your announcement:

You logged into your dormant ad account to take advantage of an exploit in our Ad Composer — to post a link that deceives users into thinking it’s a video and to artificially increase its reach.

As you may be aware, X believes everyone should… https://t.co/ziuhUOimOT

— Nikita Bier (@nikitabier) December 6, 2025

The fine, issued on Friday, was the first to be handed down under the EU’s Digital Services Act (DSA). The Commission said X’s blue tick system was “deceptive” because the firm was not “meaningfully verifying users”.

“This deception exposes users to scams, including impersonation frauds, as well as other forms of manipulation by malicious actors,” it said. It also claimed X was failing to provide transparency around its advertisements and was not giving researchers access to public data.

The social media company has been given 60 days to respond to the Commission about concerns surrounding its blue checkmarks or face additional penalties.

Following the announcement, Elon Musk posted on X saying the EU “should be abolished”, and shared a user’s response comparing the regulator to fascism.

US Secretary of State Marco Rubio and the Federal Communications Commission (FCC) accused the EU of attacking and censoring US firms, adding, “the days of censoring Americans online are over”.

The dispute emerged after Bier alleged that the Commission activated a rarely used account “to take advantage of an exploit”. He claimed the regulator had posted a link that deceived users by appearing to be a video “to artificially increase its reach”, and said the “exploit”, which had “never been abused like this”, had now been removed.

Ad accounts on X allow organisations to create and analyse paid advertising campaigns separately from their public profiles.

The fine issued last week centred on the platform’s verification system, which allows users to purchase a blue tick rather than verify their identity or credentials. The Commission said this change “deceives users” by failing to ensure accounts are genuine.

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“The fine issued today was calculated taking into account the nature of these infringements, their gravity in terms of affected EU users, and their duration,” it said. The decision marks the first enforcement action by the Commission under the DSA, which regulates how online platforms manage their data, content and advertising.

Henna Virkkunen, Executive Vice-President for Tech Sovereignty, Security and Democracy, said: “Deceiving users with blue checkmarks, obscuring information on ads and shutting out researchers have no place online in the EU. The DSA protects users. The DSA gives researchers the way to uncover potential threats. The DSA restores trust in the online environment.

“With the DSA’s first non-compliance decision, we are holding X responsible for undermining users’ rights and evading accountability.”