NEW YORK—The U.S. government sued Volkswagen Monday for installing equipment on nearly 600,000 diesel cars that intentionally subverted clean-air regulations, resulting in excess harmful emissions.

Civil penalties in the lawsuit, filed by the Justice Department on behalf of the Environmental Protection Agency, could run well above $20 billion, according to the suit.

The complaint alleges that the big German automaker intentionally installed "defeat devices" on its diesel VWs, Audis and Porsches that met tough US environmental tests during official reviews, but spewed up to 40 times the legal levels of poisonous pollutants when on the road.

The Justice Department did not specify a specific overall penalty it was seeking.

But it laid out per-car penalties of up to $37,500, and up to $2,750 per defeat device, which could take the cost of the suit for VW to well past $20 billion.

"Car manufacturers that fail to properly certify their cars and that defeat emission control systems breach the public trust, endanger public health and disadvantage competitors," said assistant attorney general John Cruden.

"The United States will pursue all appropriate remedies against Volkswagen to redress the violations of our nation’s clean air laws alleged in the complaint."

Cynthia Giles, assistant administrator for enforcement and compliance assurance at EPA, said the lawsuit would hold Volkswagen accountable and set the case on a "path to resolution."

"So far, recall discussions with the company have not produced an acceptable way forward," Giles said. "These discussions will continue in parallel with the federal court action."

Copyright Agence France-Presse, 2016