"The (European) Commission calls on national authorities to look into the implications for vehicles sold in Europe and ensure that EU pollutant emission standards are scrupulously respected," a statement from EU Industry Commissioner Elzbieta Bienkowska said.
On Tuesday, Volkswagen admitted that 11 million of its diesel cars worldwide are equipped with devices that can cheat pollution tests, after shock revelations in the US.
In Europe, France called for an investigation, while Germany called for "full transparency" in the scandal.
The Commission is responsible for setting pollution standards for automobiles in the EU but national authorities are tasked with their implementation.
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Lobbied by car companies, member states from auto-making nations including Germany and France have resisted accepting stricter pollution rules in the EU.
"Our message is clear: zero tolerance on fraud and rigorous compliance with EU rules," said Bienkowska, a former Polish development minister.
"We need full disclosure and robust pollutant emissions tests in place," she said.