After a nearly hour-long meeting, Annan said that Iran was prepared for talks ''without preconditions'' which he presumed included the issue of its nuclear enrichment programme.
''They are considering the package very, very seriously,'' Annan told journalists.
US President George W Bush said yesterday in Vienna that Iran was taking too long to respond to an offer of incentives to stop nuclear work that could lead to atomic weapons, and urged Tehran to reply within weeks.
Iran has said it will reply by August. 22 to the proposals by the five members of the UN Security Council, plus Germany, which has not been made public but is said to include incentives and penalties.
Annan said that the question of timing came up in his talks, but no specific dates were mentioned.
However, he said he did not think that any answer would come from the Iranians before the G8 group of major industrial powers meets in Russia July 15-17, which the sextet had set as an informal deadline.
''I do not think that they will give an answer before the G8 meeting in St Petersburg,'' Annan told a news conference.
MUCH AMBIGUITY Mottaki, who visited Italy before coming to Geneva to address the UN's Human Rights Council, told Italy's RAI state television that the offer contained ''much ambiguity'' and would take time to study.
Annan noted that Iran's position was that its interest in nuclear energy was purely for ''peaceful purposes''.
''I have stressed with Iranian leaders, including Mr Mottaki, that it is very much in their interest to convince the world of that by cooperating fully with the IAEA,'' he said, referring to the UN's International Atomic Energy Agency.
But he did not say whether he had received any indication from Mottaki about whether Iran was prepared to at least suspend enrichment ahead of the talks, a condition laid down by the sextet.
''Their point of view is that they are coming to the table without preconditions and that everything can be discussed at the table and that I presume includes enrichment,'' he said.
He said he also welcomed the ''policy shift'' signalled by the United States, indicating that it would be ready for talks once the issue of the suspension of enrichment had been resolved.
In the past only the so-called EU-3 -- France, Britain and Germany -- have held talks with Tehran.
''I hope that initial shifting signal will bear fruits as we move forward and that sooner rather than later we will see the US joining the talks,'' Annan said.
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