Brussels, Wed Jul 17, 2013- European Union regulators have asked Google to offer more concessions to allay concerns that it is blocking competitors in web search results, the EU's antitrust chief said on Wednesday.

The world's most popular search engine submitted its proposal to the European Commission in April to end a three-year investigation. The EU competition regulator later sought feedback from Google's rivals and third parties.

"After an analysis of the market test that was concluded on June 27, I concluded that the proposals that Google sent to us are not enough to overcome our concerns," European Competition Commissioner Joaquin Almunia told a news conference.

"In this sense, I wrote a letter to Google, to Mr Schmidt (Google's executive chairman), asking Google to present better proposals, to improve its proposal," he said.