Seat, the Spanish subsidiary of German group Volkswagen, fitted more than 500,000 cars made in Spain with the now infamous software to cheat pollution emission tests, daily newspaper El Pais reported Thursday.
Volkswagen faces a US criminal investigation and worldwide legal action after admitting that as many as 11 million of its diesel cars are equipped with software capable of fooling official pollution tests.
"The Spanish subsidiary of the German group has installed over half a million of the tampered diesel engines into its vehicles since 2009," El Pais wrote, citing unnamed sources with ties to the company.
The diesel engines used by Seat are in theory the same ones used by Volkswagen and Audi in the United States, the newspaper said.
Seat's plant in Martorell near Barcelona allegedly installed them in vehicles that were on sale until this year, it added.
A Seat spokesman confirmed that some Seat diesel vehicles were equipped with the misleading software but would not provide a figure.
Seat sold 378,586 vehicles last year and around two million vehicles, including those with both gasoline and diesel engines, over the past six years, according to El Pais.
The company has factories in Catalonia in northeastern Spain as well as in Navarra in the north.