Google is due to submit its final proposal by the end of this month to resolve EU concerns.
European Union (EU) regulators believe Google is diverting traffic and so could be forced to change its search results, according to EU antitrust chief Joaquín Almunia.
Last month, EU regulators gave Google one month to close a settlement with the EU competition authority. Almunia was quoted by the Financial Times as saying that "We are still investigating, but my conviction is they are diverting traffic [to their own services]."
"The way the US looks at abuse of dominant position is different than the European one," Almunia said.
Since 2010, the EU's antitrust regulators have been monitoring whether Google's search engine supports its own assets, including YouTube, by offering higher priority on search results pages, while actively downgrading assets of rivals, including that of Microsoft, one of the claimants.
Google is alleged to have discriminated against some sites by downplaying them in its rankings, closing down competition with advertising agreements with other websites, as well as restraining advertisers from shifting their online ad campaigns to rival search engines.
Google is due to submit its final proposal by the end of this month to resolve all EU concerns.
Last year, Microsoft asked EU antitrust regulators to intervene in a patent dispute with Google and Motorola Mobility, saying that Motorola is aggressively enforcing patent rights against rivals to stymie competition.
Recently, the US Federal Trade Commission (FTC) closed the 20-month antitrust probe into Google's web-search business that investigated whether it had manipulated its search results to favour its own services.