Mercedes has announced a £195 million plan to update three million diesel vehicles with new software to improve emissions, following alarms at parent brand Daimler.
Mercedes-Benz is also facing an investigation by the US Justice Department and the EPA in the US. Mercedes has not said the if update offer is related to the claims.
The news comes after Daimler came under pressure over accusations that it sold well over one million cars with excess emissions in 2008-2016, while German media reports that there is a search warrant against the company to investigate the claims.
The firm says that these measures will be carried out at no cost to customers.