Seattle - Microsoft Corp stepped up its rivalry with Google Inc with a formal complaint to EU antitrust regulators, claiming Google systematically thwarts Internet search competition.
It is the first time Microsoft - itself the target of anticompetition action in the United States and Europe - has filed a complaint with regulators over competition issues.
In its complaint on Thursday, Microsoft claims Google engages in a "pattern of actions" that unfairly impede competition.
Google controls more than 90% of the Internet search advertising market in Europe, well ahead of Microsoft's Bing, which is struggling to make inroads into Google's market share. Google is already under investigation by the European Commission after complaints from three small firms, one of them owned by Microsoft.
Google did not seek to counter Microsoft's claims publicly, but indicated it was not overly concerned by the complaint. "We're not surprised that Microsoft has done this, since one of their subsidiaries was one of the original complainants," Google spokesperson Al Verney said. "For our part, we continue to discuss the case with the European Commission and we're happy to explain to anyone how our business works."
The European Commission said it would review Microsoft's allegations. "The Commission takes note of the complaint and, as is the procedure, will inform Google and will ask for its views on it.
No further information will be given," EU Commission spokesperson Amelia Torres said in an emailed statement.