Iran's president warned last night that his country would respond with an "appropriate and firm response" to any UN sanction over its nuclear program.
The comments by Mahmoud Ahmadinejad came as key United Nations Security Council members were considering a draft European resolution that would impose punishing measures on Iran over its disputed nuclear program.
"Efforts by the big powers will only incite anger and hatred," Mr Ahmadinejad told a large crowd on the outskirts of Tehran.
"The Iranian nation will respond to restrictive activities with an appropriate and firm response," he said without elaborating.
Meanwhile, Mohamed ElBaradei, who heads the International Atomic Energy Agency, said at the UN that his organisation has not been able to verify that Iran's nuclear program is peaceful.
Tehran insists its nuclear efforts are solely geared at peacefully producing electricity. But the US and its allies fear Iranians want to build atomic weapons.
Russia and China, which wield veto power as permanent Security Council members, have shied away from imposing punitive measures on their trade partner Iran, saying they prefer a diplomatic solution to the impasse.
But the United States says the proposed sanctions are not tough enough.
Russian President Vladimir Putin told Mr Ahmadinejad that Moscow strongly favours further negotiations on Tehran's nuclear program, the Kremlin said.
The brief Russian statement after a telephone conversation between the two leaders was the latest indication that Russia opposes sanctions against Iran and believes the international community should try to defuse tension through talks.
With Iran waving threats of a firm response to any UN sanction, it also appeared aimed at cooling Tehran's rhetoric and casting Russia as a peacemaker.
In the Iranian-initiated conversation with Mr Ahmadinejad, "Putin outlined the fundamental position of the Russian side in favour of a continuation of the negotiation process," the Kremlin said.
President Bush insists that Washington will only agree to negotiate about Tehran's nuclear program if the Iranians first halt uranium enrichment, a key step to produce either peaceful nuclear power or an atomic bomb.
AP