US lawmakers have asked the Federal Trade Commission (FTC) to investigate Google's search engine business.
Senator Herb Kohl, a Democrat from Wisconsin, and Senator Mike Lee, a Republican from Utah, have said in a letter to the FTC that Google's search engine operations must be probed for anti-trust violations.
The senators have an issue with Google listing its own service on top of the search results. They believe that the company is taking undue advantage of its dominant position in the online search market and is using it to promote its own service above those of its rivals.
The FTC is already conducting a probe against Google's business operations but, the nature of the inquiry is not known.
"We believe these allegations regarding Google's search engine practices raise important competition issues. We are committed to ensuring that consumers benefit from robust competition in online search and that the Internet remains the source of much free-market innovation." the senators wrote in the letter [PDF].
Senators Kohl and Lee are already a part of the committee which is investigating Google's online practices. The committee, which saw executive chairman Eric Schmidt testifying before it, heard from Google's rivals that the company manipulates its search results so that its own service come on top of its rivals.