Light commercial vehicles made by Volkswagen appear to be affected by the scandal over software used to cheat US emissions tests, according to Germany's transport minister.
The US Environmental Protection Agency accused VW a week ago of installing the so-called "defeat device" in 482,000 cars sold in the United States.
VW later acknowledged that similar software exists in 11 million diesel vehicles worldwide. The German government has said that those included cars in Europe but it is not yet clear how many.
German transport minister Alexander Dobrindt said: "According to our current information, light commercial vehicles as well as cars at Volkswagen are affected by the improper manipulation of diesel engine emissions."
Meanwhile, more Volkswagen bosses are expected to fall on their swords as the German car giant's supervisory board meets over the rigging of emissions tests.
A day after long-time chief executive Martin Winterkorn resigned over the scandal, a member of VW's supervisory board said he expected more executives to step down. The board could announce new resignations as well as a new CEO when it meets today.
Attorney generals in at least 27 US states and Washington DC announced they would jointly investigate VW's representations to consumers and would send subpoenas to the company, according to the Michigan Attorney General's Office.
Olaf Lies, economy and transport minister of VW's home state Lower Saxony, which holds a 20% stake in the company, said the investigation into the scandal was only just starting.
"There must be people responsible for allowing the manipulation of emission levels to happen," he said.
Mr Winterkorn said on Wednesday he took responsibility for the "irregularities" found by US inspectors in VW's diesel engines, but insisted he had personally done nothing wrong.
VW is filing a criminal complaint with German prosecutors, seeking to identify those responsible for any illegal actions in connection with the scandal.
Later, Mr Dobrindt said 2.8 million vehicles in Germany were among those containing the software at the centre of the emissions scandal.
The European Union said it wants quick answers as to how Volkswagen was able to use stealth software in its vehicles so they could pass lab tests on emission pollution standards.
The top official responsible for the European single market, Elzbieta Bienkowska, said that "we need full disclosure and robust pollutant emissions tests in place".
Germany, Italy and France are among the countries known to be investigating, and the commission said their probes would include carmakers beyond VW.
The EU plans to introduce new emissions tests next year involving on-road monitoring. They would complement the lab tests currently used.