Iran is seriously considering the offer of negotiations on its nuclear energy plans made by the five permanent members of the UN Security Council and Germany, UN Secretary-General Kofi Annan said in Geneva yesterday.

"I believe it is considering this offer very seriously, as I have urged it to do, and I hope it will give the sufficient answer before too long," Annan told a press conference after a closed-door meeting with Iranian Foreign Minister Manouchehr Mottaki in Geneva.

The nearly hour-long talk with Mottaki was "very useful", Annan said.

Asked when Iran will make a response to the international offer, Annan said this came up in his talks with Mottaki. But he did not mention specific date.

However, he said he did not think any answer would come from Iran before the meeting of G8 group of major industrial powers in St Petersburg on July 15-17.

Iranian President Mahmoud Ahmadinejad said Wednesday that Iran will respond by mid-August to the proposals presented to Tehran in early June by EU foreign policy chief Javier Solan.

The package offered Iran incentives and fresh talks on its controversial nuclear program if it suspends uranium enrichment, but also threatened with sanctions if Iran chooses not to comply.

Iran maintains that its interest in nuclear energy is purely for peaceful purposes, Annan said.

He said he had told Iranian leaders, including Mottaki, that "it is very much in their interest to convince the world of that by cooperating fully with the International Atomic Energy Agency."