Microsoft Corp. (MSFT)’s antitrust complaint against Google Inc. (GOOG) may expand an existing European Union probe beyond Internet searches to online video and mobile phones.

Google bars rivals from search boxes on web sites, hinders advertisers from transferring campaign data between search ad platforms and blocks phones running Microsoft’s operating system from working properly with YouTube, Redmond, Washington-based Microsoft said in a blog posting by General Counsel Brad Smith.

The complaint to EU regulators in Brussels threatens to widen a probe started last year after a Microsoft unit and two other rivals last year complained that the company’s dominance chokes off advertising revenue. Google has almost 95 percent of the search market in Europe, Microsoft’s Smith said, citing data from regulators.

“These allegations cover new and difficult ground and, if Google fights, clearly increase the likelihood of a long investigation,” said Matthew Hall, an antitrust lawyer at McGuire Woods LLP in Brussels.