Staff involved in rigging pollution tests on Volkswagen cars "acted criminally" and must take personal responsibility, a board member of the German auto giant said on Tuesday.
The world's biggest carmaker by sales has revealed a plan to refit millions of vehicles affected by the scam, in which devices were fitted that switch on pollution controls when they detect the car is being tested.
German prosecutors have announced a criminal investigation of the carmaker's former chief executive Martin Winterkorn, who resigned over the scandal, while authorities in several countries have opened probes into the scam.
"Those people who allowed this to happen, or who made the decision to install this software -- they acted criminally. They must take personal responsibility," Olaf Lies, a Volkswagen board member and economy minister of the northwestern German state of Lower Saxony told broadcaster the BBC.
"Huge damage has been done because millions of people have lost their faith in VW. We are surely going to have a lot of people suing for damages. We have to recall lots of cars and it has to happen really fast."
The German government has given Volkswagen until October 7 to explain how it will resolve the scandal, which has wiped 29 billion euros ($33 billion), or 38 percent, off the company's market value in 10 days.
The controls fitted in up to 11 million diesel cars worldwide switch off when the vehicles are on the road, allowing them to emit harmful levels of emissions.
Lies said that the Volkswagen board had only found out about the issue shortly before the scandal broke this month when US officials publicly accused the company of cheating, and wanted to know why the board wasn't informed earlier.
He said that restoring trust and ensuring that ordinary Volkswagen workers were not blamed was the company's priority.
"I'm ashamed that the people in America who bought cars with complete confidence are so disappointed," Lies said.