On Tuesday, Google disclosed in a blog post that it is being investigated for anticompetitive behavior in Europe as alleged by three competitors.

Google said that the inquiry is an aftermath of the complaints by a U. K. price comparison site called Foundem, a French legal search engine called ejustice. fr, and a German search site called Ciao that was recently acquired by Microsoft.

The European Commission is Europe’s highest antitrust authority and conducts a preliminary investigation whenever it receives complaints about anticompetitive behavior. Google appears to be the object of such a preliminary probe.

Google hinted that Microsoft may be involved in two of the complaints.

Google maintained a warm relationship with Ciao, which was their long-time AdSense partner.

"However, after Microsoft acquired Ciao in 2008 (renaming it Ciao from Bing), we started receiving complaints about our standard terms and conditions. They initially took their case to the German competition authority, but it has now been transferred to Brussels", Google revealed.

On the other hand, Foundem is a member of an organization called ICOMP, which is funded partly by Microsoft, Google said.

Microsoft was not available for comment on Tuesday evening.

We have always worked hard to put our users' interests first and never resort to unfair means to succeed, Google concluded.