Brussels- An agreement between the European Union and the United States over how to share and protect data on their citizens is coming closer, but important questions remain to be solved, officials in Brussels said Wednesday.

"That there should be sharing of data for law-enforcement purposes is absolutely correct ... What we have is a set of common agreed principles, we have a set of not-yet-agreed principles, and a commitment on both sides to continuing the work," the head of the European Commission's justice department, Jonathan Faull, said.

However, ongoing talks between EU and US experts "are not about sharing data, they are not about categories of data which are going to cross the Atlantic in either direction, they are about the protection of data," he said.

Since opening talks in November 2006, the EU and the US have already agreed on 12 common principles which should govern any data- sharing deal, but have not reached agreement on five more, he said.

Principles already approved include an agreement that data should only be shared for a specific period and purpose, that there should be clear and effective oversight of the system and that sensitive information such as health or sexual orientation should only be shared in exceptional circumstances - if indeed it is collected.

The two sides have not yet agreed on the right of their citizens to the same treatment as nationals on the other side of the Atlantic, legal clarity for trans-Atlantic businesses, the impact on deals with third countries, the impact of earlier data-sharing agreements, and how the system should be managed, Faull said.

If those issues can be agreed, the commission could ask EU member states to mandate it to negotiate a formal treaty with the US. Agreement on the issues could be reached within a year, with a treaty to be negotiated thereafter, he said.

The EU and the US have been in talks on the sensitive issue of data protection and sharing ever since US officials demanded access to passenger name records (PNR) on flights from the EU to the US in the wake of the terrorist attacks of September 11, 2001.

In November 2006 the two sides set up a joint "high-level contact group" to discuss whether and how they could cooperate more closely on anti-terror and criminal investigations without breaching their different rules on data protection. (dpa)