X has blocked the European Commission from making adverts on its platform - a move which comes a few days after it fined Elon Musk's site €120m (£105m) over its blue tick badges.
Nikita Bier, who has a senior role at the social media site, accused the European Union (EU) regulator of trying to take advantage of an exploit in its advertising system to promote its post about the fine on Friday.
It seems you believe that the rules should not apply to your account, he said. Your ad account has been terminated.
A European Commission spokesperson told BBC News the Commission always uses all social media platforms in good faith.
X's fine, issued on Friday, was the first under the EU's Digital Services Act and labeled the platform's blue tick system as deceptive for failing to verify users meaningfully.
The EU noted this deception exposes users to scams and other manipulations. The Commission further stated X failed to provide transparency regarding its adverts and didn’t grant researchers access to public data.
X has been given 60 days to address the concerns surrounding its blue checkmarks or risk facing additional penalties. Following the fine, Elon Musk criticized the EU, suggesting it should be abolished and drew comparisons to fascism.
The tensions between X and European regulators were further highlighted by accusations from US officials that the EU was attacking US companies.
The dispute began with Bier's claim that the Commission had activated a rarely-used account, misleading users to think they were engaging with video content.
In response, the European Commission asserted that it was using the tools available to all corporate accounts and stressed that they expected compliance with the platforms' terms.
This incident is not unique; in recent years, X has faced penalties from various international regulators over similar issues.
