The European Commission asked the United States yesterday to confirm it was using the personal data of US-bound air passengers properly amid growing concerns over privacy rights.

An agreement between the US and Europe in October gave US law enforcement agencies easier access to personal data on transatlantic air passengers but set limits on how that data could be used.

EU Justice Commissioner Franco Frattini said he asked the US government for clarification after a description published last month in the US Federal Register about its use of the data had raised concerns among lawmakers and privacy rights groups on both sides of the Atlantic.

"We have sent today a letter to the US government to ask formal confirmation that the way European PNR (Passenger Name Record) data are handled in the ATS is the one described in the undertakings," Mr Frattini told the European Parliament.

The ATS, or Automated Targeting System, is a computerised system used by the US Homeland Security Department to scrutinise personal data on those crossing US borders and assess whether they are a terrorism or criminal threat.

Mr Frattini said there were "significant differences between the way in which PNR data are handled within the ATS on the one hand and the stricter regime for European PNR data on the other".

EU lawmakers have repeatedly expressed concern that Washington has ridden roughshod over privacy after the September 11, 2001 attacks to further a "war on terrorism".