US prosecutors warned Volkswagen and its suppliers they still faced a wide-ranging criminal investigation for their role in cheating emissions tests even as the carmaker agreed to pay $15.3bn in fines and environmental incentives.

The most costly air pollution settlement in US history includes $10bn to buy back 475,000 affected cars, $2.7bn in fines to the Environmental Protection Agency and $2bn to promote zero emission technology. It must be approved by a federal judge in California.

But while the justice department signed off on the agreement, Sally Yates, deputy attorney-general, said it was not the end of the government inquiry and federal prosecutors were “looking at multiple companies and multiple individuals” as part of their criminal probe.