Iran's top nuclear negotiator has dismissed the threat of force over its nuclear programme.
Iran insists its programme is for civil use only
Speaking in Vienna after talks with the head of the UN nuclear watchdog, Ali Larijani said the issue could only be resolved through dialogue.
Mr Larijani said Iran could offer assurances there would be no deviation towards a nuclear weapons programme.
A UN report on Wednesday is expected to say Iran has defied a 60-day deadline to suspend uranium enrichment.
Mr Larijani warned against what he called irrational moves against his country.
He said it would be met with an appropriate response.
The head of the International Atomic Energy Agency, Mohammed elBaradei, is expected to report to the UN Security Council on Wednesday that Tehran has defied a 60-day deadline to suspend uranium enrichment - opening the way for tougher international sanctions.
Earlier, President Mahmoud Ahmadinejad says those countries calling on Iran to halt its nuclear programme should shut down their own facilities for producing nuclear fuel.
Last year Iran resumed uranium enrichment - a process that can make fuel for power stations or, if greatly enriched, material for a nuclear bomb.
Tehran insists its programme is for civil use only, but Western countries suspect Iran is trying to build nuclear weapons.
Mr Larijani said at the talks at the International Atomic Energy Agency (IAEA) in Vienna: "Anybody interested in non-conventional or illogical, irrational [moves] would definitely receive an appropriate response."
Mahmoud Ahmadinejad says the UN cannot set pre-conditions for talks
But he said Iran was looking "for ways and means to start negotiations".
Speaking on the issue on a visit to Turkey, Iran's Foreign Minister Manouchehr Mottaki echoed the view.
"The way to solve problems through diplomacy is dialogue," he said.
IAEA head Mohamed ElBaradei warned in a UK media interview of the speed at which Iran's nuclear work is advancing.
In a speech to crowds in northern Iran, broadcast on state television, Mr Ahmadinejad called on Western nations to stop their own nuclear enrichment programmes if they wanted Iran to do the same.
He said: "They tell us 'come and negotiate on Iran's nuclear issue but the condition is to stop your activities.
"We have said that we want negotiations and talks, but negotiations under just conditions.'"
The US dismissed the call to close down Western production facilities.
"Do you believe that's a serious offer?" said White House spokesman Tony Snow.