The U.S. Department of Justice and the Environmental Protection Agency are suing German automaker Volkswagen for falsifying the emissions on 600,000 diesel vehicles in the U.S.

A civil complaint filed in Detroit Monday does not include criminal charges but would involve additional monetary penalties for Volkswagen, which admitted in September that it had installed software on 11 million vehicles worldwide designed to beat emissions tests.

All told, the maximum possible fine would total in the billions, and comes on top of numerous class action suits being pursued on behalf of owners.

"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," assistant attorney general John C. Cruden with the Justice Department's Environment and Natural Resources Division said.