BRUSSELS (Reuters) - Alibaba's ( BABA ) AliExpress could face a hefty fine after the European Commission on Thursday opened an investigation into dissemination of potentially illegal and pornographic materials, the third such probe after social media platform X and TikTok.

The move comes under powers granted to the EU executive from the Digital Services Act (DSA) which requires companies to do more to tackle illegal and harmful products on their platforms and followed a request for information sent to AliExpress last November.

Commission officials told reporters they were concerned about the potential dissemination of illegal products such as fake medicines, non-compliant food, and ineffective dietary supplements on AliExpress

They are also looking into possible hidden links where non-compliant products can be sold in a way that is not transparent to users and the role of influencers in this matter.

"We have not found yet at this stage that AliExpress is not compliant. We are simply suspecting we have elements that they are not compliant with. This is not a finding of a breach," one of the officials said.

AliExpress said it respected all applicable rules and regulations in the markets where it operates.

"...we have been working with, and will continue to work with, the relevant authorities on making sure we comply with applicable standards and will continue to ensure that we will be able to meet the requirements of the DSA," the company said

"AliExpress is committed to creating a safe and compliant marketplace for all consumers."

So-called VLOPs like AliExpress - or very large online platforms - are companies with more than 45 million users in Europe that are subject to the toughest DSA rules. Violations can lead to fines of up to 6% of global annual turnover.

The Commission on Thursday also sent requests for information to Microsoft's ( MSFT ) Bing, Google Search, Meta Platforms' ( META ) Facebook, Instagram, Snapchat, ByteDance's TikTok and Elon Musk's X over their use of generative artificial intelligence.

Commission officials said they want to know whether the companies conduct risk assessments and have risk mitigation measures to tackle potentially harmful generative AI content.

"We are of course concerned with the harmful category, whether it is deep fake news or election-relevant deep fakes that seek to manipulate the public environment," the officials said.

The companies have until April 3 to reply to questions related to the protection of elections and April 24 on other matters.

The growing popularity of generative AI systems such as Microsoft ( MSFT )-backed OpenAI's ChatGPT and Google's chatbot Gemini has fuelled concerns about misinformation and fake news.

The Commission also sent a request for information to Microsoft's ( MSFT ) Linkedin over the potential use of personal data for targeted advertising following a complaint from civil society organisations, giving it an April 5 deadline to respond.

The probes into X and TikTok are ongoing.