Google chairman Eric Schmidt says that Amazon is their biggest competitor when it comes to online search. He made the remark during a visit to the headquarters of Native Instruments, a software and hardware company in Berlin, Germany, explaining that while Amazon is primarily focused on e-commerce, it is essentially answering users questions and searches.

"People don't think of Amazon as search, but if you are looking for something to buy, you are more often than not looking for it on Amazon", he said, adding that since a large number of people head directly to the e-commerce website, it makes Amazon an even bigger competitor than Yahoo or Bing.

According to ComScore's media report for the month of August, Google is the No.1 site on the Internet with around 233.1 million unique visitors, while Amazon ranks sixth with around 172 million unique visitors.

In an apparent bid to counter the antitrust allegations that the Mountain View, California-based company is currently facing in Europe, Schmidt emphasized that Google is not the only search engine in the market, and it shouldn't be regulated as if it were the gatekeeper of the Internet, arguing that other companies like Facebook and Amazon are equally influential.

He also said that a large number of people are now accessing the Internet through handheld devices like smartphones, posing a tough challenge to the company, as they prefer using apps rather than heading directly to a website. "And the most popular app in the world - including in Europe - is Facebook, a company which now describes itself as the on-ramp to the internet", he said.

Although Google is currently the leader in search, Schmidt said the company's position is constantly under threat from startups. "Someone, somewhere in a garage is gunning for us. I know, because not long ago we were in that garage," he said. "Change comes from where you least expect it".

Schmidt's remarks came as a 4-year-old European Commission investigation into Google's search practices nears its conclusion. In February this year, the search giant reached a tentative settlement with European regulators, agreeing to display at least three of its rival services whenever a search result returns a link to one of Google's own services.

Last month, the Commission asked Google to make further adjustments to the settlement proposal after rivals complained that it wouldn't help them much in competing more effectively in Europe.