"The talks were not easy," a European diplomat said, while an Iranian described the negotiations as "very intense" and said the participants were "exhausted."

The talks, which began Tuesday in Geneva, were the most recent round in negotiations on Iran's nuclear program that began in December, a month after Iran agreed to a temporary suspension of enrichment to back up its claim that its atomic program is strictly peaceful.

In Brussels, EU negotiators Britain, France and Germany warned Friday that the negotiations were making slower progress than hoped, but reiterated hope that an accord could be reached.

The European trio, in an update to the EU's Luxembourg presidency, also warned that if there is no accord the EU would support a US call for Iran to be referred to the UN Security Council.

"While progress is not as fast as we would wish, we believe we are moving in the right direction ... and that we should have at least preliminary results to show from the negotiations in the period ahead," they said in a report.

The report added: "If on the other hand, despite our efforts Iran does not do so, then as has been implicit in the agreements reached with Iran and well understood by all concerned, we shall have no choice but to support referring Iran's nuclear programme to the UN Security Council," which could impose economic sanctions or even tougher measures against the Islamic Republic.

Britain, France and Germany want Iran to abandon enrichment as an "objective guarantee" that it is not developing nuclear weapons and are offering in return trade, security and technology rewards.

A new round of talks, the fifth since December, is to be held later this month, possibly in a capital of the one of the three states negotiating for the European Union -- Britain, France and Germany, a senior European dipomat said.

The diplomat said much of the discussion this week was to prepare the next meeting, which will move from the expert to a more political "steeering committee" level designed to review progress since December.

All rights reserved. � 2005 Agence France-Presse. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by Agence France-Presse. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of Agence France-Presse.