Microsoft and publishers across Europe attacked Google's antitrust deal with EU regulators, calling it a "catastrophic" proposal that would serve only to entrench its dominance of the online search market.

European Competition Commissioner Joaquin Almunia is preparing to decide on the case after spending three years examining whether Google squeezes out rival services in online search results.

The 66-year-old Spaniard, who reached a preliminary deal with the world's most popular Internet search engine in February, has around two months to issue the final decision before he leaves office. He has told 18 complainants that he intends to rebuff their grievances and is now examining their responses.

The case has become highly politicized, with sources saying about a third of Almunia's colleagues in the Commission are opposed to the deal. Sources told Reuters the EU may close the current case and open another one into Google's Android mobile operating system.

The head of British price-comparison site Foundem, Shivaun Raff, said the Commission had no evidence that Google's offer to let three rivals display their logos and web links in a box and allow content providers to decide what material Google can use for its own services would resolve competition issues.

"(Google's proposals) are not a remedy. They are a catastrophic escalation of the abuse," Raff told a news conference.

Microsoft's director of competition law, Jean-Yves Art, said the U.S. software company was particularly concerned about Google's contractual curbs on advertisers making it difficult for them to switch to other online platforms.

"The proposals don't cure or eliminate all restrictions that we and rivals see. There are still restrictions preventing them from providing interoperability," he said at the news conference.

Representatives from newspapers and magazine publishers across Europe, online travel site Expedia and a host of complainants from Germany and Britain were also present at the event.

Almunia's spokesman Antoine Colombani declined to comment. Google spokesman Al Verney did not immediately reply to emails and telephone calls.

(Editing by Tom Pfeiffer)