By Josh Ong

Published: 11:50 AM EST (08:50 AM PST)

Google has confirmed that the U.S. Federal Trade Commission is opening an investigation into the company's business practices.

In an official blog post on Friday entitled "Supporting choice, ensuring economic opportunity," the company said it had received notification from the FTC regarding the initiation of a review of its business.

"We respect the FTC’s process and will be working with them (as we have with other agencies) over the coming months to answer questions about Google and our services," the post read.

Google said the exact nature of the commission's concerns remained unclear, while continuing to vouch for the reliability and integrity of its search results. The post highlighted the company's guiding principles for search, which include:

• Do what’s best for the user.
• Provide the most relevant answers as quickly as possible.
• Label advertisements clearly.
• Be transparent.
• Loyalty, not lock-in.

"These are the principles that guide us, and we know they’ll stand up to scrutiny. We’re committed to giving you choices, ensuring that businesses can grow and create jobs, and, ultimately, fostering an Internet that benefits us all," the company said.

Rumblings of an imminent FTC antitrust investigation emerged earlier in the week. Sources close to the federal agency told The New York Times that FTC lawyers had been looking into Google's search and advertising operations for months to determine whether the company had engaged in "illegal anticompetitive behavior" in its search result rankings and advertising sales.

Google's success in the search engine market has drawn comparisons to Microsoft's Windows monopoly. As of May, Google held 65.5 percent of the U.S. search market, while Yahoo and Microsoft's Bing accounted for 16 percent and 14 percent, respectively.

During the search engine's rise to prominence, rival companies have called for antitrust investigations of Google. One organization, FairSearch.org, represents companies, including Expedia, Travelocity, Kayak and Microsoft, concerned that "Google is abusing its search monopoly to thwart competition."

"Google engages in anticompetitive behavior across many vertical categories of search that harms consumers,” the organization said in a statement. “The result of Google’s anticompetitive practices is to curb innovation and investment in new technologies by other companies.”

Apple's complicated relationship will likely come under scrutiny during the FTC investigation. Last year, the agency cited the Cupertino, Calif., iPhone maker's entry into the advertising market as a reason to approve Google's acquisition of advertising agency AdMob. Apple launched the iAd platform last year after acquiring Quattro Wireless.