The Justice Department laid out its road map on Friday to break up Google’s advertising technology empire, which would be the second request to force the company to sell pieces of its business within a year that could fundamentally alter the $2 trillion company.

The government’s comments came during a hearing convened by Judge Leonie M. Brinkema of the U.S. District Court for the Eastern District of Virginia, who ruled last month that Google had a monopoly over some portions of a sprawling system that places ads on websites. She now has to decide what measures, known as remedies, she should take to resolve her concerns.

A lawyer for the Justice Department said the government expected to ask the court to force Google to divest tools used by online publishers to sell ad space, as well as the technology that connects those publishers with advertisers looking to buy space. In the original lawsuit, the government had asked the court to force Google to sell ad technology it had acquired over the years.

To leave Google with “90 percent of publishers beholden to them is, frankly, too dangerous,” said Julia Tarver Wood, the government’s lead lawyer in the case.

Google’s lawyers said a breakup wouldn’t align with earlier legal precedent and would imperil privacy and security protections.

The Justice Department’s request is the latest legal blow to Google, which is also in the midst of a second hearing on how to remedy its monopoly over search in a federal court in Washington. In that case, the government has asked a judge to force the company to sell its popular browser, Chrome, along with other measures.