Iran has accused the US of "bullying" the UN's nuclear watchdog into drafting a resolution censuring Tehran over its nuclear programme.
Iran says the world must accept its nuclear status
Iran's foreign minister warned that Tehran may end co-operation with the International Atomic Energy Agency if Europe did not resist the US.
Kamal Kharrazi also insisted Iran would resume its uranium enrichment programme after resolving its case with the IAEA.
IAEA chief Mohamed ElBaradei warned such a move could prove very damaging.
"Iran has been in breach of its (nuclear non-proliferation) obligations for many years and we need to build confidence," Mr ElBaradei said.
"I think suspension is a confidence-building measure and, as I said, Iran needs to do everything possible right now to create the confidence required."
The IAEA's 35-nation board is meeting in Vienna this week to decide how to deal with Iran's failure to fully disclose its nuclear activities.
The IAEA's draft resolution on Iran reportedly compares Iran and Libya, saying both countries got nuclear equipment "from the same foreign sources".
However, the body has praised Libya for scrapping its nuclear weapons programme.
The agency's board of governors passed a resolution "applauding the decision by [Libya] on 19 December 2003" to renounce its weapons of mass destruction programme.
For its part, Libya has signed an additional protocol to the Nuclear Non-Proliferation Treaty (NPT) allowing snap inspections of its nuclear facilities.
Speaking to reporters after a cabinet meeting in Tehran, Mr Kharrazi said the analogy between Libya and Iran was "incorrect".
"Libya has officially announced that it was pursuing nuclear weapons and this is a violation of the NPT, but Iran has not been pursuing nuclear weapons and [has] not violated the NPT," he said.
The US has accused Iran of pursuing a clandestine programme to develop nuclear weapons and wants the matter brought before the UN Security Council, which could impose sanctions on Iran.
The BBC's Miranda Eeles in Tehran says in the draft, the US has reportedly agreed to tone down its criticism in order to win European support for a demand that Iran divulge more about its nuclear programme.
Return to production
Iran's ambassador to the IAEA, Pirooz Hosseini, said the draft was "an act of [American] bullying and putting pressure on the others".
Mr Kharrazi admonished Britain, France and Germany for backing the draft - which also praises Iran for its co-operation - after they signalled they would block a resolution in return for Iran's continued compliance with the IAEA.
"We advise the Europeans to respect their obligations and to resist American pressure, otherwise there is no reason for co-operation to continue," he told reporters.
The foreign minister said Iran intended to resume its uranium enrichment programme, which it pledged last October to suspend, "when relations with the IAEA are normalised".
BBC regional analyst Sadeq Saba says much of Iran's threatening rhetoric in defending its nuclear programme appears to be for internal consumption.
He says Tehran's more confrontational approach comes after the conservatives' victory in parliamentary elections in February altered the balance of power.
Our analyst says the conservatives know that in the eyes of ordinary Iranians, the country's nuclear programme is a source of power and pride, and they want to show that they do not bow to outside pressure.