SAN FRANCISCO - A federal judge is giving Volkswagen and regulators a month to provide a specific plan about how they will bring nearly 600,000 diesel cars into compliance with clean air laws following an emissions cheating scandal.

Senior U.S. District Judge Charles Breyer said Thursday that he wants to know the timing of the fix and any planned payments to owners by April 21, among other details.

Breyer says former FBI Director Robert Mueller told him Volkswagen, government regulators and attorneys for car owners had made substantial progress toward a resolution that would get the polluting cars off the road.

He did not provide any details.

Breyer appointed Mueller to oversee settlement talks.