In a late court filing on Tuesday, federal prosecutors also say the judge could ask the court to open the underlying data Google uses to power its ubiquitous search engine and artificial intelligence products to competitors.
Tuesday's filing is the first step in a months-long legal process to come up with remedies that could reshape a company that's long been synonymous with online search.
"For more than a decade, Google has controlled the most popular distribution channels, leaving rivals with little-to-no incentive to compete for users," the antitrust enforcers says in the filing.
"Fully remedying these harms requires not only ending Google's control of distribution today, but also ensuring Google cannot control the distribution of tomorrow."
To that end, the department says it is considering asking for structural changes to stop Google leveraging products such as its Chrome browser, Android operating system, AI products or app store to benefit its search business.
Prosecutors also zeroe in on Google's default search agreements in the filing and say any remedy proposals would seek to limit or ban these deals.
These deals lock in Google services and products as the automatic choice presented to consumers, such as when Safari browsers on Apple iPhones use Google's search engine.
Lee-Anne Mulholland, Google's vice-president of regulatory affairs, said in response to the filing that the Department of Justice was "already signalling requests that go far beyond the specific legal issues" in this case.
"Government overreach in a fast-moving industry may have negative unintended consequences for American innovation and America's consumers."
In a landmark case in August, US District Judge Amit Mehta ruled Google's search engine had been illegally exploiting its dominance to squash competition and stifle innovation.
He has outlined a timeline for a trial on the proposed remedies next spring and plans to issue a decision by August 2025.
Google has already said it plans to appeal Mehta's ruling, but the tech giant must wait until he finalises a remedy before doing so.
In November, federal prosecutors will submit a more detailed proposal on tackling Google's anti-competitive practices.
Google in turn will offer its own ideas for how to make fixes in December. Prosecutors will then make their final proposal in March 2025.
Google has faced intensifying regulatory pressure on both sides of the Atlantic, with European Union antitrust enforcers also suggesting that breaking up the company is the only way to satisfy competition concerns about its digital ad business.
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