By Foo Yun Chee

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

Under the EU's newly adopted Digital Services Act (DSA), AliExpress has been designated as a very large online platform (VLOP) and together with 15 other tech companies has to do more to tackle illegal and harmful content on its platform.

The EU executive had sent a request for information to AliExpress in 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, and the lack of effective measures to tackle these.

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, which risks a fine of up to 6% of its global annual turnover, 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."

The Commission on Thursday also sent requests for information to Microsoft's Bing, Google Search, Meta Platforms' 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-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 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.

"LinkedIn complies with the DSA, including its provisions regarding ad targeting. We look forward to cooperating with the Commission on this matter," the company said.

The probes into X and TikTok are ongoing.

(Reporting by Foo Yun CheeEditing by Nick Macfie and Mark Potter)