Russia warned on Wednesday that a military strike on Iran would be a ‘catastrophe’ with the severest consequences that risked inflaming existing tensions between Sunni and Shiite Muslims.
Foreign Minister Sergei Lavrov also accused the West of trying to suffocate the Iranian economy and incite popular discontent with new sanctions such as a proposed oil embargo.
"As for the chances of this catastrophe happening, you would have to ask those constantly mentioning it as an option that remains on the table," Lavrov said when asked about the chances of military action.
Israeli Defence Minister Ehud Barak had earlier said his country was not even close to deciding to attack Iran over its nuclear weapons programme and still believed that a military options remained "very far away".
Lavrov said the chances of war were too dire too contemplate because they would incite inter-communal tensions in the region and flood neighbouring countries with Iranian refugees.
"I have no doubt in the fact that it only add fuel to the fire of the still-simmering Sunni-Shiite conflict. And I do not know where the subsequent chain reaction will end.
"There will be large flows of refugees from Iran, including to Azerbaijan, and from Azerbaijan to Russia.
"But this is only one of the problems and far from the most important one. This will not be a walk in the park," he said of possible military involvement.
Lavrov added that punitive sanctions aimed at winning more transparency from Iran had "exhausted" themselves and only hurt the chances of peace.
"Additional unilateral sanctions against Iran have nothing to do with a desire to ensure the regime's commitment to nuclear non-proliferation," Lavrov told reporters at an annual briefing outlining Russia's foreign policy views.
"It is seriously aimed at suffocating the Iranian economy and the well-being of its people, probably in the hope of inciting discontent."
His comments came as EU diplomats closed in on a July date for a full oil embargo that would suit nations such as Italy with a strong reliance on Iranian supplies.
Lavrov said Russia had evidence that Iran was ready to cooperate more closely with inspectors from the United Nations IAEA nuclear watchdog and was preparing for "serious talks" with the West.
He also hinted that Europe and the United States were imposing the measures with the specific purpose of torpedoing new rounds of talks.
Russia has been one of the few world powers to enjoy open access to senior Iranian leaders and on Wednesday hosted its Supreme National Security Council deputy chief Ali Bagheri.
The Iranian embassy said Bagheri would hold talks with Lavrov and discuss the option of resuming nuclear negotiations with the five permanent members of the UN Security Council and Germany.
Tehran's ambassador to Moscow for his part said he expected Russia's support to continue because it too was being threatened by the West.
"We expect Russia not to agree to a deal with the West," Iranian Ambassador Mahmoud Reza Sajjadi told the Interfax news agency.
"If there are (non-Western) countries that want to see Iran become a victim of the West, they must understand that the West will get to them too," Sajjadi.
"We hope that the Russian government and the Russian people will take note of this."