Any move to involve the UN Security Council in the row over Iran’s nuclear programme would mean the end of diplomacy, a top Iranian official says.
The warning, issued by chief Iranian nuclear negotiator Ali Larijani, follows an agreement by key powers to report Tehran to the council.
The move was announced following talks in London between the US, Britain, Russia, China, France and Germany.
Iran denies Western claims that it is aiming to build nuclear weapons.
Iranian state television quoted Mr Larijani as saying that informing the Security Council or referring the case would bring an end to diplomacy.
At the late-night talks in London, the five permanent council members plus Germany agreed the International Atomic Energy Agency (IAEA) should report Iran to the Security Council when the agency’s board meets in Vienna on Thursday.
However they added that the council would take no action until March, after it had received a report from the IAEA.
The move stops short of the formal referral urged by the US, Britain and France.
BBC diplomatic correspondent James Robbins says the decision to choose the weaker option of reporting Tehran to the council acknowledges divisions among members.
A US diplomat told Reuters news agency: “This is the most powerful message we could have hoped for.”
US President George W Bush, previewing his State of the Union speech to be delivered on Tuesday, said he would have separate messages for the Iranian people and their government.
“And in speaking to the people, my message is this: ‘You know, we’re not going to tell you how to live your life, but we would like you to be free’,” he said.
“But to the government, our message is that if you want to be a part of the family of nations, give up your nuclear weapons ambitions.”
He added: “We’re united in our goal to keep the Iranians from having a weapon, and we’re working on the tactics necessary to continue putting a united front out.”
Iran insists it should be allowed to develop nuclear technology, but other key powers do not want it to produce its own enriched uranium, which can be used in nuclear weapons as well as power plants.