Google has confirmed that it is under investigation in the EU for possible violations of the "abuse of dominant position" portions of the Lisbon Treaty, as several websites accused the American giant of manipulating its search rankings to penalize them.

The UK’s Daily Telegraph newspaper reports that price comparison site Foundem posted a blog entry on its site as long ago as last August, saying that "Google has always used various penalty filters to remove certain sites entirely from its search results or place them so far down the rankings that they will never be found."

However, the companies behind the complaint have various types of ties to Microsoft, Google’s main rival in the search arena, a fact which Google was not slow to point out. The company’s senior competition counsel, Julia Holtz, blogged that "while we will be providing feedback and additional information on these complaints, we are confident that our business operates in the interests of users and partners, as well as in line with European competition law."

Experts say that European search engine optimization (SEO) could be affected in the future if any further action is taken on the case.