Google was yet to issue an official statement on the development.
A Congressional report published earlier this month accused Google of favouring its own products in search results, a similar charge levied by the anti-trust competition authorities in Europe.
Earlier, The Wall Street Journal reported that the case will mark the most aggressive US legal challenge to a company’s “dominance in the tech sector in more than two decades”.
Last year, the EU antitrust regulators fined Alphabet $1.7 billion for unfairly restricting rivals from displaying ads on its platform via third parties using its AdSense tool. Google was also fined a record $5 billion by European antitrust authorities in 2018.
The WSJ report said that the lawsuit accused Google of engaging in anticompetitive behaviour in its search and search advertising businesses.
On 22 September, The New York Times reported that the Justice Department had narrowed its case to focus on Google’s dominant position in search.
The Justice Department began investigating Big Tech firms in July last year.
This is the biggest antitrust case against a tech company since the Microsoft case in 1998.