"The threats of sanctions have no effect on us, the Europeans used double-standard approach and therefore have lost their credibility," government spokesman Gholam-Hossein Elham told a weekly news briefing.

"We have been ready to face all scenario, we control the energy sources, so the West, especially the United States will lose more," he added.

On Sunday, Iran's parliamentary speaker Gholam-Ali Hadad-Adel warned the country would withdraw from the International Atomic Energy Agency (IAEA) if its "inalienable rights" are deprived of.

"If depriving Iran of its inalienable rights is the result of its membership in international organizations, including the IAEA, our withdrawal from such bodies is well justified," said the speaker.

The UN Security Council on July 31 adopted a resolution by a vote of 14 to 1, urging Tehran to "suspend all enrichment-related and reprocessing activities, including research and development" by Aug. 31 or face the prospect of sanctions.

Due to insistence of council members such as Russia and China, the resolution dropped the threat of immediate sanctions and required the council to hold further discussions before sanctions are considered.

Iranian officials have recently expressed indignation over the UN demand to halt enrichment activities, warning the United Nations against taking acrimonious measures to force Iran to comply or Iran would quit the NPT and stop cooperation with the IAEA.

The United States has accused Iran of secretly developing nuclear weapons under a civilian front, a charge categorically denied by Tehran which says that its nuclear program is for peaceful purposes.