"We will respond next month (according to the Iranian calendar)."

He said several committees were studying the offer and that Iran would deliver its response "sometime" after July 23.

World powers on Thursday gave Iran one more week to provide a "clear and substantive response" to an international proposal over the long-running crisis over Iran's nuclear programme.

The five permanent UN Security Council members -- Britain, China, France, Russia and the United States -- plus Germany have offered Iran a package of incentives that includes multilateral talks if it agrees to temporarily halt uranium enrichment.

That work is at the centre of fears the hardline regime could acquire nuclear weapons, although oil-rich Tehran insists the project aims only to provide fuel for nuclear energy.

Rejecting allegations that Iran was seeking to buy time, Asefi said: "It is not a question of tactics and wasting time. It is a multi-dimensional package and takes time to examine".

"There are ambiguities (in the package) which need to be discussed with the Europeans," Asefi added.

"We will submit a logical response considering our country's rights and interests," he said, referring to the demands for a freeze in enrichment, a process which provides fuel for nuclear plants but can also form the core of an atomic bomb.

"Alleviating the West's concerns should not be interpreted as sacrificing our interests," Asefi added.

Iran's top nuclear negotiator Ali Larijani and EU foreign policy chief Javier Solana are to meet in Brussels on Wednesday on the international package.

"The two sides will talk about their views on removing ambiguities and reaching a result," Asefi said.

The United States said Friday it expected Iran to respond at the meeting between Larijani and Solana, who submitted the proposed packed to Tehran on June 6.

"We've seen lots of political statements from lots of political figures. We are waiting for the authoritative channel which is the Larijani channel to Solana," US Under Secretary for Political Affairs Nicholas Burns said in Brussels.

He added that the international community was "unified" around the offer to Tehran. "We all believe that negotiations make sense and that Iran should accept the offer," he said.

"It's now up to Iran to decide. It's high time frankly that we had a response from the Iranian government."

Iran's hardline President Mahmoud Ahmadinejad had set August 22 as the date for Tehran's response.

Hitting out at world "bullies", Ahmadinejad said Saturday that Tehran would continue uranium enrichment and accused world powers of seeking to prevent technological advancement in developing countries.

"The Iranian government and the people have decided, and without any doubt with dignity and glory we will pass this phase," Ahmadinejad said at an African Union summit in Gambia.

The world powers will meet on July 12 to assess the Iranian response and decide whether it is enough to allow a resumption of negotiations -- or warrants bringing the issue back to the UN Security Council for possible punitive measures.

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