BRUSSELS: The European Union rebuked Iran on Wednesday in unusually direct language, suggesting it was willfully delaying new nuclear talks with six world powers by changing venues and setting preconditions on how the negotiations should be conducted.

The criticism appeared provoked by an announcement by Iranian Foreign Minister Ali Akbar Salehi that his country was now proposing Cairo as the host city of the next meeting. Salehi said Egypt welcomed the proposal and was in contact with the six powers - the United States, Russia, China, Britain, France and Germany - on the issue.

Diplomats from some of those world powers have expressed frustration in recent weeks about what they say are Iran's tactics of proposing several venues but not committing to any single one. But the comments Wednesday by the spokesman for EU foreign policy chief Catherine Ashton were the first to voice that sentiment on record.

Ashton has acted as the convener of previous talks. The comments, by Michael Mann, her spokesman, were clearly meant to put the responsibility on Tehran for lack of agreement on a venue and date for such a meeting, despite weeks of consultations.

"We proposed concrete dates and venues in December," he told reporters. "Ever since then, we have been very surprised to see Iran come back to us again and again with new preconditions on the modalities of the talks, for example by changing the venue and delaying their responses.

"We have always been very flexible and have been in regular contact with them as part of an ongoing process."

The two sides have not revised plans to meet by the end of this month. But with less than two weeks remaining in January, that date may have to be delayed unless agreement on a venue is reached soon.

Iran has been trying to reach out to Egypt since the February 2011 fall of President Hosni Mubarak, seeking to resume relations with the Arab state and extend its influence in the Middle East.

The last round of nuclear talks ended in stalemate in Moscow in June, triggering new international sanctions that have been pressing hard on the Iranian economy.

The West demands that Iran halt its highest-level uranium enrichment, which Washington and others fear could quickly be turned into nuclear warhead-grade material.

Iran insists it does not seek nuclear arms - repeatedly citing a 2005 edict by Supreme Leader Ayatollah Ali Khamenei that called atomic weapons a violation of Islamic tenets - and says it only wants to enrich to make fuel for present and planned reactors.

Iran's leaders know the only route to ease the economic pressures - and possibly undercut threats of military action on its nuclear sites by Israel - is through potential deal-making with the six world powers.

If the talks restart, they would be the first negotiations since the West stepped up unilateral sanctions against Tehran last summer, including a total oil embargo and banking restrictions that make it increasingly difficult for Iran's Asian customers to pay for oil deliveries.

Iran depends on oil sales for about 80 percent of its foreign currency revenue. Its income from oil and gas exports has dropped by 45 percent as a result of the sanctions, and the West is waiting to see if the measures force Tehran to make concessions at the negotiating table.

The six-nation group wants Iran to halt its 20-percent level of uranium enrichment, close down its underground Fordo enrichment site and ship out that higher-grade enriched stockpile.

Iran says it will never give up its right to enrich uranium but has indicated it may be willing to suspend the 20-percent level enrichment in return for specific concessions from the West, such as lifting the sanctions.

"We want to see Iran come back to the negotiating table as soon as possible so that we can make concrete progress towards dealing with the international community's concerns about the Iranian nuclear program," Mann said.