FILE PHOTO: The Daimler logo is seen before the Daimler annual shareholder meeting in Berlin, Germany, April 5, 2018. REUTERS/Hannibal Hanschke

FRANKFURT (Reuters) - Germany's road vehicle authority KBA has found five "illegal switch-off devices" in Daimler DAIGn.DE car engines, newspaper Bild am Sonntag (BamS) reported on Sunday.

The authority said it suspected the emissions control devices were being used in the bulk of Daimler’s new Euro 6 diesel car fleet, encompassing some 1 million vehicles, according to the report.

A Daimler spokesman said he would not comment on the BamS story, adding, “We are cooperating to a full extent and transparently with the KBA and the federal transport ministry.”

He reiterated previous Daimler comments objecting to the KBA stance that switch-off devices were in breach of regulations.

Daimler, like other car manufacturers, uses urea nitrate liquids to naturalize nitrogen oxide emissions in exhaust fumes. However, the KBA has taken issue with the emission control features amid suspicion they allow vehicles to emit excess pollution without detection.

Daimler said last month it would appeal against an order by the KBA to recall the Mercedes van Vito 1.6l Diesel Euro 6 model, following a transport ministry investigation.

Since rival Volkswagen VOWG_p.DE admitted in 2015 to cheating U.S. emissions tests, German carmakers including VW, Daimler and BMW BMWG.DE have faced a backlash against diesel technology in which they have invested billions of euros.

Daimler boss Dieter Zetsche is set to meet with German Transport Minister Andreas Scheuer on Monday, after they met last week to discuss diesel emissions.