"It is not decided yet," Mottaki told reporters on the sidelines of a pan-Islamic conference in the capital of Azerbaijan, as US President George W. Bush upped the pressure on the Islamic republic ahead of a US-European Union summit.

Mottaki said Iran still had "doubts" over a carrot-and-stick plan to coax Iran into negotiations over its nuclear program, which the United States and Europe fear could be hiding atomic weapons development.

"I can't say for the time being when the answer will be finalized. There can be some questions and doubts which should be clarified," he said, speaking in English.

The United States and its partners -- Britain, France, Germany, as well as Russia and China -- have made Iran's suspension of uranium enrichment and reprocessing activities a condition for talks on Tehran's atomic program.

So far Tehran has indicated it rejects that pre-condition.

International negotiators have set a June 29 deadline for Iran to respond but Mottaki said Iran was "working on the proposal of the six countries" and denied there was any time limit.

"When this package was offered no deadline was given for our answer."

Bush leaves Tuesday for a US-EU summit in Vienna that will examine, among other issues, the package offer to Iran.

On Monday, he warned of "progressively stronger political and economic sanctions" if it refuses to freeze sensitive nuclear activities in return for talks.

Mottaki called Bush's comments a "threat" and "unacceptable."

"It's as though some have forgotten that the time of threats is over. Threats are unacceptable in today's world," he said, adding that "the political rights of Iran must be respected."

With Iran suggesting that it will soon unveil its own proposal for ending the crisis over its atomic programs, Bush signalled that the suspension of uranium enrichment and reprocessing was not negotiable.

"If Iran's leaders want peace, and prosperity, and a more hopeful future for their people, they should accept our offer, abandon any ambitions to obtain nuclear weapons, and come into compliance with their international obligations," Bush said in a speech to the graduating class at the US Merchant Marine Academy in King's Point, New York.

Mottaki is due to visit Italy on Wednesday for talks with his counterpart Massimo D'Alema, the semi-official Fars news agency reported.

Mottaki also attacked what Tehran perceives as Western-sponsored ethnic unrest in Iran after members of the ethnic-Azeri minority in the country rioted in May in protest over the publication of an offensive cartoon in an Iranian newspaper.

"Any plan to make divisions among Iranian people was always defeated," Mottaki said, adding: "We do not let a third party to interfere in our relationship."

Mottaki said all of Iran's minorities had a place in its society.

"Iranian, Azerbaijani, Turkmen, Baluchistani, Kurdish: All have important roles in running the country," he added.

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