While attempting to convince the U.S. Senate antitrust committee that Google is not a monopoly, Google chairman Eric Schmidt stated that Apple’s Siri could pose a serious threat to the company’s core business. From AppleInsider:

Eric Schmidt, Google’s chairman and former chief executive, admitted to the U.S. Senate antitrust subcommittee that Apple’s new Siri personal assistant technology is a “significant development” in search and could pose a threat to his company’s core business.

This should come as no surprise. The U.S. government is investigating whether Google classifies as a monopoly, so it makes sense for Google to defend itself with whatever they have available. As it stands, Siri is only available on a single device, so Google citing the fledgling technology comes across as an act of desperation to get the government off their back.

If Apple decides to implement Siri on more devices, and continues to pull results from non-Google sources like Yelp and Wolfram|Alpha, then Google may have a valid reason to be concerned. Considering that 2/3 of all mobile searches on Google come from iOS devices, having Siri pull the results from alternative sources could hit Google hard.