BRUSSELS (Reuters) - Google competitors have called for further action by European Union antitrust regulators to ensure the Alphabet-owned GOOGL.O firm treats rivals offering shopping services equally.

FILE PHOTO: The Google logo is seen at the "Station F" start up campus in Paris, France, February 15, 2018. REUTERS/Benoit Tessier

Last year, Google said it would allow competitors to bid for ads at the top of a search page, giving them the chance to compete on equal terms, after the European Commission fined it a record 2.4 billion euros ($2.9 billion).

“Google’s remedy proposal is, on its face, non-compliant with the prohibition decision,” a group of 19 rivals said in a letter to European Competition Commissioner Margrethe Vestager.

Google said it was complying with the EU order.

British price comparison site Foundem, whose complaint triggered the EU investigation, France’s Twenga and rivals in travel search, digital mapping and publishing were among the signatories to the letter to Vestager.

“Google’s current remedy proposal is no better than Google’s Commitment proposals under Commissioner Almunia, and in some ways may be worse,” the group said, referring to Vestager’s predecessor who tried to get Google to settle without a fine.

The EU competition authority said it was aware of the concerns and has sought feedback from both rivals and Google.

“The letter raises several arguments that the Commission has already been looking at as part of its ongoing assessment of Google’s measures,” an authority spokesman said on Wednesday.

Google spokesman Al Verney said the U.S. company was giving competitors a fair chance.

“As required, comparison shopping services have the same opportunity as Google Shopping to show shopping ads from merchants on Google’s search results pages,” Verney said.

Google could be fined up to 5 percent of its average daily worldwide turnover if it fails to comply with the EU order.

EU regulators hit Microsoft with an 899 million euro ($1.1 billion)penalty in 2008 for not complying with a 2004 ruling and another 561 million euro fine in 2013 for not complying with a 2009 decision.