The nominee to become the EU's top justice official slammed Thursday the quick introduction of body scanners at airports, saying the devices could invade travellers' privacy.
"I am convinced that body scanners have a considerable privacy-invasive potential. Their usefulness is still to be proven," said Viviane Reding, who is currently EU telecoms commissioner but in line to take over the justice post.
"Their impact on health has not yet been fully assessed. Therefore I cannot imagine this privacy-intrusive technique being imposed on us without full consideration of its impact," she said in a speech in Brussels.
The United States has accelerated the installation of body scanners at airports since the attempted Christmas Day attack on a jet bound for Detroit from Amsterdam.
It wants the EU to follow suit to monitor passengers crossing the Atlantic.
Several European countries, including Britain and the Netherlands, are to install the scanners after Nigerian Umar Farouk Abdulmutallab was charged with trying to down the passenger plane.
But other EU nations are cool on the idea despite the US pressure, and the EU commission wants to see health and efficiency studies on the machines before looking at rules to introduce them across the bloc.
EU members can currently use the devices, which can "see" through clothing, as they see fit.
Many members of the European parliament have opposed an EU-wide move to install scanners.
But Europe's anti-terror coordinator, Gilles de Kerchove, said Wednesday that it is important to rapidly complete studies on their impact.