In a court filing, the US Department of Justice urged a shake-up of Google's business that includes banning deals for Google to be the default search engine on smartphones and preventing it from exploiting its Android mobile operating system.

Antitrust officials said in the filing that Google should also be made to sell Android if proposed remedies don't prevent the tech company from using its control of the mobile operating system to its advantage.

Calling for the breakup of Google marks a profound change by the US government's regulators, which have largely left tech giants alone since failing to break up Microsoft two decades ago.

Google is expected to make its recommendations in a filing next month and both sides will make their case at a hearing in April before US District Court Judge Amit Mehta.

Regardless of Judge Mehta's eventual decision, Google is expected to appeal the ruling, prolonging the process for years and potentially leaving the final say to the US Supreme Court.

The case could also be upended by the arrival of President-elect Donald Trump to the White House in January.

His administration will likely replace the current team in charge of the DOJ's antitrust division.

The newcomers could choose to carry on with the case, ask for a settlement with Google, or abandon the case altogether.

Trump has blown hot and cold in how to handle Google and the dominance of big tech companies. 

He has accused the search engine of bias against conservative content, but has also signaled that a forced break up of the company would be too large a demand by the US government. 

Determining how to address Google's wrongs is the next stage of the landmark antitrust trial that saw the company in August ruled a monopoly by Judge Mehta.

Google has dismissed the idea of a breakup as "radical."

Adam Kovacevich, chief executive of industry trade group Chamber of Progress, said the government's demands were "fantastical" and defied legal standards, instead calling for narrowly tailored remedies.

The trial, which concluded last year, scrutinized Google's confidential agreements with smartphone manufacturers, including Apple. 

These deals involve substantial payments to secure Google's search engine as the default option on browsers, iPhones and other devices.

The judge determined that this arrangement provided Google with unparalleled access to user data, enabling it to develop its search engine into a globally dominant platform. 

From this position, Google expanded its tech and data-gathering empire to include the Chrome browser, Maps and the Android smartphone operating system.

According to the judgment, Google controlled 90 percent of the US online search market in 2020, with an even higher share, 95 percent, on mobile devices.

The US government currently has five cases pending against big tech over antitrust concerns after the Biden administration adopted a tough stance on reining in the dominance of the companies.

If carried through by the Trump administration, the cases against Amazon, Meta, and Apple, as well as two against Google, could take years to litigate.