Microsoft Corp. has filed its first-ever formal complaint to European Commission regulators, claiming that Google Inc. systematically impedes Internet search competition, Reuters reported.

The action, taken on Thursday, is indicative of the rivalry between Google, which operates the world’s largest search engine, and Microsoft, which has been a target of antitrust action for two decades in the United States and Europe.

“The filing of this complaint reflects one of the greatest ironies of antitrust history,” said Thomas Vinje, global head of antitrust practice at Clifford Chance, who led a coalition that won European Union fines against Microsoft.

The complaint, which also underscores the erosion of Microsoft’s near-monopoly of the personal computer market, claims Google engages in a “pattern of actions” that unfairly thwarts competition.

Google controls more than 90 percent of the Internet search advertising market in Europe. And though Microsoft’s Internet Explorer leads the way in the Web browser market, the Mozilla Foundation’s Firefox and Google’s Chrome have chipped away at the software maker’s position.

“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,” said Google spokesman Al Verney, adding that the company isn’t overly concerned about the complaint.