The EU's anti-trust chief is widely expected to unveil anti-trust charges against Google's Android, the world's most popular mobile phone operating system, as she faces reporters on Wednesday.
The European Commission, the powerful executive arm of the 28-nation European Union, said in a statement that Competition Commissioner Margrethe Vestager would hold a press conference at 0930 GMT.
Chief commission spokesman Margaritis Schinas said in a tweet Vestager would unveil "an important competition case." But contacted by AFP, a spokeswoman refused to confirm or deny the topic of news conference would be the case against Google.
Several sources told AFP on Tuesday the EU would formally take aim at Google's Android mobile phone platform in a potentially huge setback for the Silicon Valley giant.
The EU is looking at whether Google gives unfair prominence to its own apps such as maps or music streaming in deals with mobile manufacturers such as Samsung or Huawei.
EU regulators "need to be sure that big companies don't try to protect themselves by holding back innovation," Vestager said in a speech on Monday.
"That's why we’re looking closely at Google’s contracts with phone makers and operators which use the Android operating system," she said.
The case would be the second attack by the EU against Google. Last year the EU formally charged the company for abusing its dominance of the search engine market in Europe.
In both cases, Google risks a fine of 10 percent of worldwide global sales for one year, which would amount to a $7.4 billion fine on the basis of 2015 revenues.
Android is seen as crucial to Google's future as customers increasingly rely on smartphones and tablets for their computing needs instead of traditional PCs.