Iran said Sunday that it won't stop uranium (search) reprocessing work, rejecting a European threat that Tehran (search) had less than two weeks to freeze uranium conversion or face referral to the U.N. Security Council (search) for possible sanctions.

Iran resumed uranium reprocessing activities at its Uranium Conversion Facility (search) in Isfahan in central Iran last month. The facility converts uranium concentrate ore, known as yellowcake, into uranium hexaflouride gas, the feedstock for enrichment.

In the next stage, Iran could feed the gas into centrifuges used to enrich uranium at its uranium enrichment plant in Natanz, also in central Iran. Iran says it won't restart uranium enrichment for now in Natanz, where it was suspended in 2003 under a deal with Europeans, but insists it will never again suspend uranium conversion in Isfahan.

Uranium enriched to low level is used to produce nuclear fuel used to generate electricity, but further enrichment makes it suitable for use in nuclear weapons.

The United States accuses Iran of using its civilian nuclear program as a cover to secretly produce nuclear weapons. Iran has rejected the charges, saying its nuclear program is geared merely towards generating electricity, not a bomb.

Iran restarted work in Isfahan after it rejected a European package of proposals that had called on Iran to permanently stop its uranium enrichment program in return for a supply of nuclear fuel and economic incentives.

Tehran said the proposals were against the spirit of the Nuclear Nonproliferation Treaty and against previous agreements between Iran and the Europeans, which had recognized Iran's right to use nuclear energy for peaceful purposes.

Iran says it won't give up uranium enrichment, a right granted to it under the Nonproliferation Treaty.

A report by Mohamed ElBaradei, head of the International Atomic Energy Agency, said on Friday that Tehran had recently produced about seven tons of the gas it needs to enrich uranium — a possible pathway to a nuclear weapon — after restarting work in Isfahan.

Britain, Germany and France, negotiating on behalf of the 25-nation European Union, have said they may get involved in drafting the language of a resolution demanding that Iran be referred to the Security Council if Tehran fails to stop uranium conversion in Isfahan by the upcoming IAEA board meeting on Sept. 19.

"The issue of Isfahan is a thing of the past," Foreign Ministry spokesman Hamid Reza Asefi told reporters Sunday.

Asefi said ElBaradei's report does not justify Iran's referral to the Security Council and said Europeans must stop threatening Iran.

"The era of threats to force Iran to give up its rights is over. We have said it and say it again, that threat and resorting to two-sided language won't help Europe," he told a press conference.

Meanwhile, an Iranian official noted that ElBaradei's report gave Iran credit for cooperating with the agency, but also included sections that would give Europeans the excuse to bring political pressures on Iran.

"ElBaradei confirms that traces of highly enriched uranium, which had been used by America as a sign that Iran was moving towards nuclear weapons, were due to contaminated equipment imported into Iran. This is a big victory for Iran," Mohammad Saeedi, Deputy Head of the Atomic Energy Organization (search) of Iran, told state-run television Sunday.

"But it has also used a language that gives Europeans the pretext to pressure Iran, which is not acceptable," he said.

Saeedi said Iran won't answer some questions by ElBaradei simply because the demands he made are beyond his agency's responsibilities.

"They have asked us to explain where do we keep dual-use equipment we have imported and similar demands. These demands are beyond IAEA's responsibility," he said.