The European Union on Monday urged carmakers to "behave more ethically" and responsibly, following a scandal over diesel emissions, and revelations of diesel exhaust tests on monkeys and humans.
EU commissioner for industry Elzbieta Bienkowska told deputies in the European parliament that she will ask all member states "to verify that such tests on human and animals are not being conducted".
Last week it emerged that German auto giant Volkswagen tried to keep secret the results of a diesel emissions test on monkeys because it showed a worse health impact than expected.
Amid a storm of criticism over the experiment and over separate tests on German human volunteers commissioned by an auto industry-financed research institute, VW suspended its chief lobbyist Thomas Steg and labelled the testing "unethical and repulsive".
Bienkowska told the MEPs assembled in Strasbourg that "the car industry has to behave more ethically and responsibly," adding the EU Commission, the bloc's executive arm, was "shocked" by the news of the tests conducted on animals and humans.
The experiments, revealed in a New York Times article, were commissioned by a now defunct research body funded by Daimler and fellow German auto giants BMW and Volkswagen.
The same organisation, the European Research Group on Environment and Health in the Transport Sector (EUGT), also carried out tests on human volunteers.
"There is no EU law that justifies such behaviour," she stressed, especially coming after the "Dieselgate" scandal.
The scandal was sparked by Volkswagen's 2015 admission that it had fitted out millions of cars with software that enabled them to cheat pollution tests.
Some 52 percent of Germans said they had "lost confidence" in the auto industry in a poll published last month, while a sizeable majority of 73 percent said politicians treated the vital sector too leniently.