PARIS/STOCKHOLM, Dec 18 (Reuters) – The European Union on Monday said it would launch an investigation of social media company X, formerly known as Twitter, over a suspected breach of obligations in its first such probe under the Digital Services Act (DSA).

The DSA, which entered into force in November last year, requires very large online platforms and search engines to do more to tackle illegal content and risks to public security, and to protect their services against manipulative techniques

The proceedings will focus on countering the dissemination of illegal content in the EU, and the effectiveness of measures taken to combat information manipulation, notably of the “community notes” system, the Commission said.

It will also focus on the measures taken by X to increase the transparency of its platform and a suspected deceptive design of the user interface such as checkmarks linked to subscription products, the so-called Blue checks.

The Commission said it will now carry out an in-depth investigation as a matter of priority and continue to gather evidence by sending additional requests for information, conducting interviews and inspections.

X, owned by Elon Musk, is part of a group of large tech companies facing increased scrutiny under the DSA.

Following Hamas’ attacks on Israel on Oct. 7, EU industry chief Thierry Breton sent letters to X, Meta (META.O), TikTok and Alphabet (GOOGL.O) reminding them of their obligations under the DSA to tackle harmful and illegal content.

The platforms responded promptly to Breton, highlighting steps they have taken to stop disinformation on their platforms but Musk challenged Breton over the disinformation charge.

Only X received a formal request for information under the DSA and has responded to the request.

The Commission said a preliminary investigation conducted so far included an analysis of a report submitted by X in September, X’s transparency report published in November, and X’s replies to a formal request for information about illegal content in connection to Hamas’ attacks against Israel.

X did not immediately respond to Reuters requests for comment.

The DSA imposes new rules on content moderation, user privacy and transparency. Any firm found in breach faces a fine worth up to 6% of its global turnover.