EU Competition Commissioner Joaquin Almunia set an early July deadline for the world's most popular search engine to resolve the concerns of more than a dozen rivals, including Microsoft, or face formal charges.

"We have made a proposal to address the four areas the European Commission described as potential concerns. We continue to work cooperatively with the Commission," Google spokesman Al Verney said in a statement on Monday.

He declined to provide details.

Almunia's spokesman Antoine Colombani confirmed that the EU watchdog received a letter from Google's executive chairman, Eric Schmidt, on Monday in reply to Almunia. He gave no details.

Almunia in May identified four areas of concerns related to Google's business practices following an 18-month long investigation.

He said Google may have favoured its own search services over those of rivals and may have copied travel and restaurant reviews from competing sites without their permission.

He also said the company's advertising deals with websites may have blocked rivals while its contractual restrictions may prevent advertisers from moving their online campaigns to rival search engines.

The FairSearch coalition, whose members include online travel agencies and Google complainants Expedia and TripAdvisor, said it hoped Google's proposals would address the issues.

"We hope the proposals reflect a greater willingness to end Google's anti-competitive behavior than has its consistent rejection of the concerns that Almunia identified after collecting evidence for nearly two years," FairSearch's lawyer Thomas Vinje said in a statement.

• A Permanent Economic Emergency