Volkswagen America's chief executive, Michael Horn, said the company "totally screwed up," candidly admitting wrongdoing after the German car giant was caught cheating in US pollution measuring tests.

Horn pledged late Monday to "make things right with the government, the public, our customers, our employees and also very important, our dealers."

"Our company was dishonest, with the EPA and the California Air Resources board, and with all of you and -- in my German words -- we have totally screwed up," Horn said at an event in New York.

Volkswagen, the world's largest automaker by sales, has revealed that 11 million diesel cars worldwide are equipped with devices that can cheat pollution tests.

The scandal went public Friday when US regulators ordered the company to fix the defect and said they were launching a probe.

US authorities said the company had acknowledged that it had equipped about 482,000 diesel VW and Audi cars in the US with software called a "defeat device" that covertly turns off pollution controls when the car is being driven and turns them on only when it detects that the car is undergoing an emissions test.

With the device off, the car can spew health-threatening pollutant gases into the air, including nitrogen oxide in amounts as much as 40 percent higher than emissions standards, said the US Environmental Protection Agency.

The US Justice Department has reportedly launched a criminal investigation and the scandal has also led to France calling for a Europe-wide probe into the revelations and South Korea summoning Volkswagen officials.

The German firm halted all diesel vehicle sales in the United States during the US probe, which could lead to fines of more than $18 billion.

Speaking at an event to launch the 2015 Passat, Horn said Volkswagen was "damn committed" to turning the scandal into an opportunity to learn and improve, adding the company's future depended on it.

Horn also said VW would pay what it has to.

"You can be sure that we will continue not only to correct this TDI issue and to straighten things out and to pay what we have to pay but we will continue to work very hard to make

our story here in the US for the customers, our dealers, our employees, successful," he said.

Volkswagen has said it was setting aside $7.3 billion (6.5 billion euros) in provisions for the third quarter to cover the potential costs of the fallout.

VW shares plunged 17 percent on Monday, followed by another 23 percent Tuesday to a low of 101.30 euros during trade on the Frankfurt stock exchange.