A German media research consortium reported Wednesday that German automaker Daimler, the maker of Mercedes-Benz cars, had cheated emissions tests on two of its lines of engines for almost 10 years.

The allegations prompted a series of raids carried by German authorities on a number of Daimler locationsback in May.

Read more: Daimler trying to dispel Dieselgate fears

According to a joint investigation by Germany's WDR and NDR broadcasters, and the "Süddeutsche" newspaper, Daimler's OM 642 and OM 651 engines used an illegal defeat device to power down the engine during emissions tests. Those two engines are thought to be in one million vehicles sold across Europe and the US.

Reports suggest that it could also lead to Germany's Federal Motor Transport Authority (KBA) forcing the Stuttgart-based carmaker to recall the tens of thousands of affected cars, at least in Europe. US regulators and prosecutors would likely pursue their own legal charges.

Rival carmaker Volkswagen used a similar device to cheat emissions tests, which ultimately led to the so-called Dieselgate scandal and the company having to pay out some 22.6 billion euro ($25.8 billion) in fines and compensation.

German prosecutors are also reportedly looking to charge two specific Daimler employees for allegedly misleading customers into buying the cars through false advertising. Further employees may also face similar charges.

A Daimler spokesperson told German media that it does not comment on ongoing investigations but insisted that the automaker was complying with the authorities.

Stuttgart prosecutors have been investigating Daimler over alleged emissions cheating and misleading advertising since March.

More trouble ahead?

US prosecutors also reportedly have their sights set on the German carmaker, where it faces a number of class action law suits by car owners, who claim Daimler understated the emissions levels for a number of diesel-powered models.

The automaker had agreed last year with the KBA to "voluntarily" recall 247,000 vehicles to update "potentially problematic technology," allegedly installed to prevent engines from being damaged.

However, as recently as March, Daimler's head, Dieter Zetsche, dismissed allegations that the carmaker was guilty of breaching emissions laws.

dm/gsw (Reuters, AFP, sz)