The European Union (EU) has reached a preliminary agreement in the long-running dispute over the handling of personal data about EU citizens flying to the US, a European Commission spokesman said.

Franco Frattini, the commissioner for justice and home affairs, together with German Interior Minister Wolfgang Schaeuble and US secretary for homeland security Michael Chertoff, reached the agreement on Wednesday.

However, details won't be made public until after a meeting of ambassadors for all 27 EU countries slated for this morning, said Friso Roscam Abbing, Frattini's spokesman. The ambassadors will have to sign off on the deal, which observers say is likely to happen.

US authorities have been trying to use the renewal of a transatlantic agreement permitting the transfer of European air passengers' data, known as passenger name records (PNRs), to beef up their powers of surveillance of foreigners entering the US.

Sharing the data breaches strict European data protection laws, but the European Commission and national governments in the 27 countries in the EU negotiated an exemption from the rules in order to allow the US to better protect itself from potential terrorist attacks. That interim agreement was deemed illegal by the European Court of Justice and the court gave the EU until the end of July to come up with a new accord.

Failure to do so would leave European airlines exposed to massive fines and the possible loss of landing slots in the US if they don't continue to hand over the data, or legal action on data protection grounds in the EU if they do.

Roscam Abbing declined to comment on reports that the political agreement reached Wednesday allows US authorities to hold onto PNR data for 15 years. "Wait until the briefing tomorrow," he said.