Ali Larijani, secretary of Iran's Supreme National Security Council, told reporters he would give a preliminary response next week to a package of economic, technological and political incentives designed to entice Iran to halt uranium enrichment.

"We are serious about continuing negotiations and will start next Tuesday with talks," he told reporters on meeting EU foreign policy chief Javier Solana in Brussels. The two men are due to meet again next week.

Pressed to say if he had brought with him an initial answer to the major powers' package, which Solana delivered to Tehran on June 6, Larijani said: "We will talk about it Tuesday."

A US official later told State Department reporters in an email that Larijani did not respond to the proposal during his meeting with Solana.

The European Union said talks with Iran late on Thursday on a package of incentives to end a nuclear standoff were constructive and laid the basis for a fuller response by Tehran at a second meeting due next week.

"It's a good start for what we expect will be a positive meeting on July 11," Cristina Gallach, spokeswoman for EU foreign policy chief Javier Solana said on Friday of his two-hour meeting with Iran chief nuclear negotiator Ali Larijani.

"We expect on Tuesday that they will be able to give us a substantial response," she said of a long-awaited reply to a package of technology, trade and other incentives for Iran to halt uranium enrichment.

Asked whether the EU was confident Iran would have given a full answer by the time of a summit of Group of Eight industrial powers in St Petersburg on July 15, she said:

"We want to create the conditions for the start of negotiations as soon as possible ... I have always said we are not using the word 'deadlines'," she said, adding that the summit and an earlier meeting of major power foreign ministers on July 12 were nonetheless key dates.

She gave no details on the content of the talks between Solana and Larijani, which she described as a "tete-a-tete" meeting with just an interpreter, saying only that Solana stressed the benefit to Iran of accepting the offer.

Solana is due to host Larijani for a second round of talks in Brussels on July 11 with the countries behind the offer, the five permanent members of the UN Security Council plus Germany, also to be present at the meeting.

UN nuclear watchdog head Mohamed ElBaradei earlier warned Iran the world was running out of patience because it had not replied to the proposals.

"The Iranian counterpart authorities told me that they need some time to provide the response," ElBaradei, who heads the International Atomic Energy Agency (IAEA), told reporters in Ankara after talks with Turkish Prime Minister Tayyip Erdogan.

"I think they need to make sure that everybody in Iran is on board. But by saying that I hope that Iran also understands that the international community is getting somewhat impatient. The earlier they can provide an answer is better for everybody."