The U.S. Federal Trade Commission may soon be adding its name to the list of government agencies investigating Google's dominance of Internet search.

The FTC is awaiting the Justice Department's decision on Google's planned acquisition of airline flight and ticket information provider ITA Software before initiating a probe, according to a Bloomberg report that cited people familiar with the matter. The FTC shares antitrust oversight with the Justice Department, which is expected to issue a decision soon on the $700 million deal.

Google representatives did not immediately respond to a request for comment.

The ATI deal has raised concerns among rival search engine companies such as Microsoft and online travel companies, including Expedia and Travelocity. They have all argued against the deal, saying that it would give the search giant a monopoly over online travel searches.

Google fields nearly 67 percent of Internet searches in the U.S., according to ComScore market research, and that domination has led to increased scrutiny of the company over the past several years.

Microsoft filed an official complaint with the European Union last week, claiming that Google is engaging in anticompetitive behavior in Internet search and online advertising, as well as other sectors. (Microsoft general counsel Brad Smith explained the company's rationale in a blog.)

Microsoft was adding its voice to a probe that began when European regulators sent a letter to Google in February 2010 asking the company to explain how it ranks search results and advertising after European price-comparison sites complained that Google penalized their Web sites in search results under competitive pressure.

The Texas attorney general's office followed suit with its own antitrust review in September 2010, demanding that Google turn over a broad range of internal documents, including its formula for determining advertising rates and information on the company's closely guarded algorithms that run its search engine and AdWords, Google's system for displaying ads with keyword search results. Ohio and Wisconsin are also said to be considering antitrust probes.