The European Commission swiftly rejected a call by the European Parliament on Wednesday to reconsider rules banning airline passengers from carrying liquids through airport security checkpoints.
The assembly adopted a non-binding resolution calling on the executive Commission to review the regulations and repeal them if "no further conclusive facts are brought forward" about their impact on preventing terrorist attacks.
But European Transport Commissioner Jacques Barrot said in a statement that in the face of terrorist threats, "Europe must not show any sign of weakness. It must not lower its guard but on the contrary reinforce its vigilance and maintain the full range of prevention instruments it has adopted."
The EU limited air travelers to carrying small containers of liquids or gels in sealed plastic bags after British authorities last year said they had foiled an attempt to blow up aircraft using liquid explosives.
Duty-free items bought at airports outside the EU became a casualty of the new rules.
Passengers who bought whisky or after-shave outside Europe and carried them as hand luggage had to surrender them when changing planes in the EU, even though the items were purchased after security checkpoints in the departure country.
The Commission said in July it would apply new measures to allow passengers to keep such products if purchased in countries with security standards that match those of the 27-nation EU.
The resolution expressed lawmakers' concern that "the costs engendered by the regulation may not be proportionate to the added value achieved by additional security provisions."
The resolution does not oblige the Commission to review the rules, and Barrot said: "This regulation cannot be abrogated as long as the threat of liquid explosives exists and we have not developed other effective means of countering it."
In addition to passenger safety, it would be wrong to expose airlines to the economic consequences of a bomb attack which would be far greater than the inconvenience of such prevention measures, he added.
Parliament members cited complaints from citizens about inconvenience and the cost of buying bottled drinks behind security checkpoints as reasons to look at the rules again.
The European Travel Retail Council (ETRC), which represents tax- and duty-free shops across Europe, had welcomed the move by parliament.
"We welcome any practical review of the rules which will make it easier for our retailers and passengers. But in the short term we will continue to work within the new rules adopted by the Commission (in July), which were a step in the right direction," ETRC President Frank O'Connell told Reuters.