The U.S. Justice Department told a federal judge Alphabet's Google illegally dominated online advertising technology in seeking a second antitrust win against the company.

Judge will decide whether the internet giant, already facing the prospect of a breakup over its monopolistic search engine, also runs its advertising unit as an illegal monopoly.

A federal judge will hear arguments on whether Google's advertising tech constitutes a monopoly as closing arguments begin Monday.

Canadian regulators say Google abused its position as the largest adtech provider in the country. It's the latest in a series of legal challenges brought against the tech giant. Canada's antitrust watchdog is suing Google over its anti-competitive conduct in its adtech business, the country's Competition Bureau said Thursday.

Canada's Competition Bureau is suing Google for alleged anti-competitive conduct in its online advertising. In a statement, the country's antitrust watchdog alleged Google had illegally linked two advertising tools to maintain market supremacy and used this dominant position to distort ad auctions by preferring its own tools.

The Bureau is demanding that Google divest two of its key advertising technology tools—DoubleClick for Publishers (DFP) and AdX—and pay a penalty to comply with the country's

Canada's Competition Bureau says that an investigation found the company "unlawfully" tied together its ad tech tools to maintain its dominant market position.

Canada's competition watchdog filed a lawsuit against Google on Thursday, accusing the U.S. tech giant of having abused its dominance in the advertising technology space to maintain its market superiority.

Canada's antitrust watchdog is suing Google to force the breakup of the company’s ad tech unit. In a statement published Thursday, during the US Thanksgiving holiday, the Competition Bureau said a “thorough” investigation had found that Google had abused its dominant position in programmatic web advertising to “maintain and entrench its market power.