But US and European officials said the Iranian ploy was backfiring and Tehran, unwilling to risk diplomatic isolation, was unlikely to follow through.
Iran is waging an aggressive multi-pronged offensive to resume uranium enrichment and halt snap inspections of its nuclear sites. The latest efforts are aimed at persuading next month's International Atomic Energy Agency (IAEA) board meeting to end an inquiry into its nuclear activities.
"We don't think it's appropriate to try to intimidate the atomic energy agency or its board into overlooking many failures of Iraqn to meet its non-proliferation commitments," US State Department spokesperson Richard Boucher said.
"We don't think it's appropriate to try to intimidate the atomic energy agency or its board into overlooking many failures of Iraqn to meet its non-proliferation commitments"
US State Department spokesperson
Boucher's comments came after Iranian President Mohammed Khatami said in Tehran the IAEA's June decision "will have an influence on our cooperation with the agency."
US officials said the Iranian attempt at intimidation included threats to deny some imports from Australia, which has joined the United States in demanding complete answers about the Islamic republic's nuclear intentions.
"Iran is clearly trying to up the ante ahead of IAEA meeting but I don't take the threats too seriously," said a senior official.
If Iran withdrew from the nuclear Non-proliferation Treaty - including the prohibitions against uranium enrichment and the requirement for IAEA inspections - it "would become a pariah to everyone" and ally itself with North Korea, another official said.
With such threats, the Iranians are further "digging themselves into a hole," a European diplomat said.
Iran has persistently denied US claims that the Islamic republic is producing nuclear weapons, maintaining that it's nuclear programme is for peaceful purposes.
Iran last week submitted what it says is a full declaration of its nuclear activities and has urged the IAEA board of governors to remove Tehran's case from its agenda.