The European Union signalled on Thursday it could give the United States limited access to its police databases in a bid to resolve a long-running visa row with Washington.

The offer, likely to stir up European concerns about data privacy, would be an attempt to get all 27 EU member states into the U.S. visa-free system. But it would apply only if the EU received similar data from Washington, a senior EU official said.

"We are prepared to sit down with our American friends and discuss on a strictly reciprocal basis what information may be needed to be shared to include our member states in the visa waiver system," Jonathan Faull, the EU executive's director for justice and home affairs, told a news conference.

Among its databases, the EU stores asylum seekers' fingerprints and plans to do the same with visa applicants. Countries in its Schengen border-free area also have a database for people searched by police and for stolen vehicles.

Faull said the EU would not give full access to its databases but needed to confer with the United States to see what data it wanted.

Most old EU states are part of the U.S. visa waiver programme, which allows their citizens to travel without visas. But Greece and 11 of the 12 mostly ex-communist countries that joined the bloc in 2004 and 2007 are not.

Washington this year pressed those countries to give it access to police data in return for scrapping visas, but had not offered to give any of its police data in return, Faull said.

The Bush administration's decision to sign separate, preliminary visa deals in recent weeks with several ex-communist central European countries instead of with the EU as a whole has caused tensions within Europe and with Washington.

Those deals did not include access to EU databases.

The EU and the United States agreed last month to defuse the crisis for now by allowing talks between Washington and individual EU states to run in parallel with EU-U.S. talks.

On Friday, EU justice and interior ministers are expected to give the European Commission a formal mandate to negotiate on EU matters.

Faull said that would include the issue of access to databases as well as a planned U.S. electronic travel authorisation system, which would require travellers to fill in a form on the internet before departure.

Countries like the Czech republic, which signed preliminary deals with the United States, have said they will go ahead with their own talks and do not want EU-U.S. talks to delay their entry into the visa waiver system.

Faull said the EU was not holding things up.