BRUSSELS — The European Union said on Monday that Google Inc. must in "a matter of weeks" outline steps it is willing to take to ease concerns about alleged abuses of its dominant position in the online search market.

European antitrust chief Joaquin Almunia said that after a 1 ½ year investigation the EU had pinpointed four specific areas of concern and insisted the problems needed to be dealt with quickly because the high-tech industry changes so rapidly.

"Restoring competition swiftly to the benefit of users at an early stage is always preferable to lengthy proceedings," Almunia said.

Google, the world's most popular search engine, also faces a similar antitrust investigation by the Federal Trade Commission in the United States.

The EU's concerns, brought on by complaints from Google's rivals, center on how the internet giant deals with its search results, how content is used and how advertising is run on its search engine.

Almunia suggested it was in the interests of both the 27-nation EU and Google to find a quick resolution to the antitrust concerns. The investigation could drag on for years, by which time the market in the fast-evolving internet sector may have rendered the EU's concerns obsolete. At the end of an investigation, however, Google could face a fine of up to 10 percent of its annual revenue.

Almunia noted Google had committed to discuss the antitrust issues and avoid legal action from the EU.

"This is why I am today giving Google an opportunity to offer remedies to address the concerns," he told reporters.

At the start of the probe in November 2010, three competitors, one owned by Microsoft, said that links to their services appeared too low on Google's general search results. They also noted that when Google, which is based in Mountain View, Calif., offers similar services, such as online price comparison, it put its own links higher on the sponsored search results, the ones companies have to pay for.

The EU Commission's investigation also assessed whether Google prevented advertising partners from placing ads from Google's competitors on their sites.

On Monday, Almunia said that Google displays some links to its own vertical search services differently than it does for competitors. "We are concerned that this may result in preferential treatment."

He also said Google might be picking up content from competitors and using it without prior authorization. "We are worried that this could reduce competitors' incentives to invest."

A telephone request to Google for comment was not immediately returned.

ICOMP, an internet business group which is sponsored by Microsoft, said it welcomed Almunia's statements.

"It is vital that the terms of any agreed settlement include measures to quickly redress the harm caused to European businesses and consumers and are sufficiently robust to ensure that such harm is not repeated," said ICOMP counsel David Wood. "We trust that this will prove to be the case and a competitive online market place will be restored."