The Justice Department on Thursday announced a sweeping antitrust lawsuit against Apple, accusing the tech giant of engineering an illegal monopoly in smartphones that boxes out competitors, stifles innovation and keeps prices artificially high.

The lawsuit, filed in federal court in New Jersey, alleges that Apple has monopoly power in the smartphone market and leverages control over the iPhone to “engage in a broad, sustained, and illegal course of conduct.”

“Apple has locked its consumers into the iPhone while locking its competitors out of the market,” said Deputy Attorney General Lisa Monaco. Stalling the advancement of the very market it revolutionized, she said, it has “smothered an entire industry.”

Apple called the lawsuit “wrong on the facts and the law” and said it “will vigorously defend against it.”

The suit takes aim at how Apple allegedly molds its technology and business relationships to “extract more money from consumers, developers, content creators, artists, publishers, small businesses, and merchants, among others.”

Apple has defended the walled garden as an indispensable feature prized by consumers who want the best protection available for their personal information. It has described the barrier as a way for the iPhone to distinguish itself from devices running on Google’s Android software, which isn’t as restrictive and is licensed to a wide range of manufacturers.

“Apple claims to be a champion of protecting user data, but its app store fee structure and partnership with Google search erode privacy,” Consumer Reports senior researcher Sumit Sharma said in a statement.