Russia, Iran's nuclear partner, said on Thursday it saw no evidence Tehran was breaching the global nuclear non-proliferation regime. Iran angered the European Union and the United States by resuming uranium conversion work earlier this month, rejecting EU incentives offered in return for giving up its nuclear programme.
"There is no reason to think that the existence of this threat has been proved," Russian Foreign Minister Sergei Lavrov was quoted by state news agencies as saying.
"If a threat to the non-proliferation regime appears, we will work seriously on that matter," he added.
Under the Non-Proliferation Treaty, (NPT), which Iran has signed, Tehran may process and enrich uranium for peaceful purposes.
The oil-rich state insists its nuclear programme is aimed only at the peaceful generation of electricity, but the West fears Iran is seeking to make atomic weapons.
Russia, which has built a nuclear power station for Iran, said earlier this month it opposed using force to stop Iran's nuclear programme and warned that any such action would have grave and unpredictable consequences.
Russia has not directly taken part in the EU's talks with Iran but the West carefully monitors diplomatic moves by the permanent member of the UN Security Council, one of Iran's staunchest supporters. If Iran continues to defy international pressure, Europe and the United States are likely to press the United Nations' nuclear watchdog to refer Iran's case to the UN Security Council for possible sanctions, analysts say.
US President George W. Bush has said military force remains a last resort to press Tehran to abandon its nuclear ambitions.