FRANKFURT — German prosecutors on Tuesday said they were searching business premises across the country as part of an investigation into suspected diesel emissions cheating involving Mitsubishi cars.

Frankfurt prosecutors said they had opened a fraud investigation against senior employees at "an international car group", two international car suppliers and a car dealership.

Japan's Mitsubishi Motors is in a three-way alliance with Renault and Nissan. The group is one of the world's biggest automakers.

Prosecutors said the probe focused on Mitsubishi diesel vehicles with 1.6- and 2.2-litre engines that were given Germany's highest Euro 5 and Euro 6 ratings depending on their adherence to emissions standards.

"There is a suspicion that the engines are equipped with a so-called shutdown device" that makes them appear less polluting in lab tests than they actually are on the road, the prosecutors' statement said.

Police officers were raiding 10 commercial sites across Germany, including in the states of Hesse, Bavaria and Lower Saxony, they added.

A spokesman for German car supplier Continental confirmed to AFP that three of its locations had been searched as part of the probe.

The firm was acting as "a witness" and fully cooperating with the probe, he added.

A spokesman for rival German car parts manufacturer Bosch told AFP they were not involved in the raids.

The Mitsubishi probe is the latest fallout from the so-called dieselgate scandal that erupted in 2015 when the Volkswagen group admitted to installing software in 11 million vehicles worldwide to dupe pollution tests.

The "defeat devices" allowed the affected cars to spew out up to 40 times more harmful nitrogen oxide than legally allowed.

The scandal has since ensnared a string of car companies, although Mitsubishi had so far avoided being dragged into the diesel controversy.

But the Tokyo-based firm did in 2016 admit to falsifying fuel-economy tests for 25 years to make the cars seem more efficient than they were.

The raids come at a sensitive time for Mitsubishi's three-way alliance.

The globally dominant car group has been dogged by scandal since the shock arrest in Japan of former chief Carlos Ghosn on charges of financial misconduct in 2018.

Ghosn made international headlines last month after he jumped bail and fled to Lebanon -- apparently by hiding in a large case for audio equipment on a private jet.

He denies the charges against him, claiming they were cooked up by disgruntled Nissan executives hoping to block his plans to more closely integrate the automaker with Renault.

Ghosn has since claimed the car alliance was on the rocks, forcing Nissan last week to deny reports it was working on secret plans to possibly dissolve the alliance.

The "dieselgate" saga meanwhile has cost the Volkswagen group -- which includes Audi, Porsche, Skoda and Seat -- over 30 billion euros ($33 billion) to date in fines, compensation and buybacks.

Car supplier Bosch, accused of supplying key components of Volkswagen's defeat devices, has also paid hundreds of millions of euros in fines at home and the United States but denies any wrongdoing.

Luxury automaker Daimler also denies cheating but nevertheless agreed to pay an 870-million-euro fine to German authorities last year for having sold vehicles that did not meet legal emission limits. — AFP