* EU wants to track cash of terrorism suspects    

* Data privacy cloud US anti-terror efforts in Europe    

BRUSSELS - Credit card companies such as Mastercard and Visa may be forced to share transaction data with European Union authorities under plans to investigate terrorism financing in Europe, due to be presented on Wednesday.    

The EU's executive Commission is set to unveil plans for a mechanism to collect and monitor financial information linked to terrorism suspects that would mirror similar efforts in the United States, EU officials said.    

Like their US counterparts, EU investigators would rely largely on data about bank transfers, collected by companies such as the Society for Worldwide Interbank Financial Telecommunication (SWIFT).    

But EU officials say the scope of the programme could be extended to other sources of information about cash used by people suspected of terrorist activities, such as credit-card or money transfer companies.    

"Other providers can also include credit companies," one Commission official told Reuters, speaking on condition of anonymity.    

Policymakers have pushed for the creation of a European system to track suspect cash and complement efforts in the United States because of concerns over data privacy when data is shared with investigators outside Europe.    

Such worries had dogged talks between the EU and the United States over sharing bank transfer data provided by SWIFT last year and had led the European Parliament to veto a deal, before Washington agreed to more privacy safeguards.    

As part of a deal giving Washington access to SWIFT data, US policymakers agreed last year to help the EU create its own programme to track suspect cash.    

US investigators have tracked cash linked to terrorism suspects since the September 11, 2001, attacks on the United States.

They say the data collected has helped investigations into numerous attacks in Europe, such as the 2004 bombings in Madrid and those in London in 2005.    

But the amount of data transferred has been a cause of concern for EU lawmakers who say passing data about EU citizens in bulk violates their rights.    

Setting up a European programme would alleviate some concerns, but the process is likely to take years. EU governments, and the parliament, will have decide exactly how data should be collected and used.    

In a document to be presented on Wednesday, and seen by Reuters, the European Commission will suggest several options for creating the mechanism, with varying level of involvement by EU governments.