BRUSSELS - More than 20 price comparison websites across Europe on Wednesday criticized Google's proposed changes to its search results, saying they still fail to comply with EU tech rules and urged regulators to impose charges against the Alphabet unit.

Google has been discussing with comparison sites, hotels, airlines, restaurants and retailers for more than a year now on how to comply with the Digital Markets Act (DMA), which prohibits it from favoring its products and services on its platform.

Last month, it announced its latest proposal, which includes expanded and equally formatted units to allow users to choose between comparison sites and supplier websites.

ALSO READ: NYT: Google spends 15 years creating culture of concealment

It may also bring back its old "ten blue links" format from years ago as an alternative if it can't agree with its rivals. This format is now being tested in Germany, Belgium and Estonia.

The price comparison websites, which include Germany's Idealo and billiger.de, France's Le Guide, PriceRunner, Kelkoo and kieskeurig.nl and trovaprezzi.it, said Google has not listened to their feedback.

READ MORE: Google says it has cracked a quantum computing challenge with new chip

"Google has simply, repeatedly, ignored this feedback, and instead continued to iterate on the same non-compliant solution for months," they said in an open letter.

"If Google has not taken feedback into account after more than 100 events, it can only mean one thing: Google is wilfully not complying with the DMA."

READ MORE: FT: Brussels probes Google-Meta secret ads deal targeting teens

When asked for comment, Google referred to its Nov 26 blog post where it pointed to the many changes it had made over the past year to comply with the DMA and find a solution.

The websites called on the European Commission to act against Google.

"The Commission has opened proceedings against Google for non-compliance. It must proceed with such proceedings, issue preliminary findings, and impose fines on Google, including periodic penalty payments, to force Google to finally listen and comply," they said.