Emissions cheating revelations spark angry calls across the European Union for a probe.
Switzerland has banned sales of Volkswagen Group car models which may have been outfitted with devices designed to tricking emission tests.
The ban – announced on Friday – is on all cars with diesel engines in the Euro 5 emissions category, including VW, Seat, Skoda and other brands in the VW group.
Thomas Rohrbach, spokesman for the Swiss federal office of roadways, said the move could potentially affect 180,000 vehicles that have 1.2-litre, 1.6-litre and 2.0-litre diesel engines.
But the ban does not include the cars that are already in circulation.
Matthias Mueller, who was appointed as CEO of the embattled German carmaker on Friday to deal with the emissions scandal, pledged to do everything to win back the trust of the public.
“We stand by our responsibility,” he said.
According to the United States authorities, VW has admitted that it equipped about 482,000 cars in the US with sophisticated software that covertly turns off pollution controls when the car is being driven.
It turns them on only when it detects that the vehicle is undergoing an emissions test.
With the so-called “defeat device” deactivated, the car can spew pollutant gases into the air, including nitrogen oxide, in amounts as much as 40 times higher than emissions standards, said the US Environmental Protection Agency (EPA).
The EPA is conducting an investigation that could lead to fines amounting to a maximum of more than $18bn.
VW said the scandal involved 11 million vehicles worldwide.
The Volkswagen Group includes 12 brands, and the company has yet to detail fully what cars where were involved.
A Volkswagen statement on Friday said some diesel models and model years – such as the sixth-generation Golf, seventh-generation Passat and first-generation Tiguan – are equipped exclusively with the EA 189 engines in which it says there are “discrepancies”.
Volkswagen brand chief Herbert Diess said, “We are working at full speed on a technical solution that we will present to partners, to our customers and to the public as swiftly as possible.”