BRUSSELS (AFP) - Major world powers expressed disappointment Friday that Iran has "not responded positively" to a plan for resolving the standoff over its nuclear programme or agreed to new talks.

"We are disappointed by the lack of follow-up" to understandings reached when the six powers met with Iranian officials in Geneva on October 1, they said in a statement after a meeting in Brussels.

"Iran has not responded positively to the IAEA (International Atomic Energy Agency) proposed agreement for the provision of nuclear fuel for its Tehran research reactor," they said.

"Iran has not engaged in an intensified dialogue and in particular has not accepted to have a new meeting," permanent UN Security Council members Britain, China, France, Russia and the United States, plus Germany, added.

Many in the West suspect that the Islamic republic is covertly trying to build a nuclear weapon with highly-enriched uranium. Tehran insists it is only developing a civil energy programme, and has rejected attempts to force it to stop uranium enrichment.

In an attempt to draw Iran into talks and guarantee that its nuclear ambitions are peaceful, the six have offered to reprocess some of its low-enriched uranium abroad.

This uranium would have been converted into nuclear fuel and returned to Iran to power a research reactor in Tehran.

But on Wednesday, Iran rejected those plans brokered by the IAEA.

A senior EU official said the six did not discuss any further specific sanctions against Tehran, but that they planned to forge ahead with a dual-track strategy combining political and economic incentives with the threat of coercive action.

"They (sanctions) were not discussed in specific terms. There was a general discussion on sanctions. Why not? The answer is that all of these things are a matter of timing, and this was not the right time," he told reporters.

The head of the IAEA, Mohamed ElBaradei, holds out little hope for the talks, or the carrot and stick approach of incentives backed by the threat of sanctions currently being used.

"I think the Group of Six are partly meeting in an environment of desperation," he said in Berlin. "I haven't really talked to them but again, they talk about the dual track, but to me the second track is a dead-end street."

Despite this, the EU official, speaking on condition of anonymity insisted: "The dual track strategy remains the strategy."

ElBaradei also said he did not consider Iran's answer to be its last word.

"I do not consider that I have received a final answer," he said.

"We have not received any written response from Iran. What I got of course is an oral response, which basically said 'we need to keep all the material in Iran until we get the fuel,'" he said.

He said: "I believe that frankly the ball is very much in the Iranian court. I hope that they will not miss this unique and fleeting opportunity."

However the senior EU official said: "There have been so many statements from Tehran from different people. It's difficult to know what is the official Iranian response."

"The one thing that is clear is that we have not had a positive response," added, saying: "We have all drawn the conclusion that the Iranians have not accepted the offer. But the Iranians are very good at never quite saying no."