"The European Union is rejecting purchases of Iranian oil, even though very many EU countries depend on this oil," Foreign Minister Sergei Lavrov said in an interview on state-run Rossiya 24 television.
"One can say, of course, that the deficit will be covered, but (some) refineries are geared specifically to Iranian oil ... and readjusting them will demand substantial investments that the EU can hardly afford now," he said.
Lavrov reiterated Moscow's opposition to any further UN sanctions and actions by other nations and groups, including the EU oil ban which comes into force in July.
"The unilateral sanctions to which our Western partners resort, bypassing the Security Council, only strengthen ... those in Iran who are sure the West is not interested in resolving issues linked with non-proliferation of nuclear technologies, but is interested in regime change," Lavrov said.
Speaking ahead of a second round of talks next month between Iran and the six world powers - Russia, China, the United States, Britain, France and Germany - he suggested the focus should be on coaxing Tehran into cooperation with the prospect of relief from sanctions.
Russia has been calling for a "step-by-step" resolution to the dispute.
Iran should be presented with "a concrete and realistic road map, a kind of program that would be based on the principle of an action for an action," Lavrov said.
He repeated Russia's proposal that as a start, Iran could freeze the number of centrifuges for uranium enrichment at current levels, while global powers would refrain from imposing new sanctions and freeze a number of boycotts and embargos already imposed against Tehran.
The idea is that "if Iran starts steps to meet the demands of the UN Security Council and the International Atomic Energy Agency - let's say, not increasing the number of centrifuges - as a response, certain sanctions will also be frozen and will not be expanded," Lavrov said.
If Iran then reduced the number of centrifuges, some sanctions would be withdrawn, and eventually Iran's "uranium enrichment would be frozen for the period of negotiations" aimed to dispel all doubts about the peaceful nature of its nuclear program, he said, according to a transcript of his comments.
"And after that the freeze on enrichment would be lifted" and Iran could produce nuclear fuel for a peaceful energy program under IAEA control, he said.
Russia says the centrifuge proposal was discussed at an initial round of negotiations earlier this month. Iranian and Western officials have said little about the proposal.
Washington and its Western allies accuse Iran of trying to develop nuclear weapons under the cover of a civilian nuclear program, while they have never presented any corroborative evidence to substantiate their allegations. Iran denies the charges and insists that its nuclear program is for peaceful purposes only.
Tehran stresses that the country has always pursued a civilian path to provide power to the growing number of Iranian population, whose fossil fuel would eventually run dry.
Despite the rules enshrined in the Non-Proliferation Treaty (NPT) entitling every member state, including Iran, to the right of uranium enrichment, Tehran is now under four rounds of UN Security Council sanctions for turning down West's calls to give up its right of uranium enrichment.
Tehran has dismissed the West's demand as politically tainted and illogical, stressing that sanctions and pressures merely consolidate Iranians' national resolve to continue the path.
Yet, after over a year of stalled talks, Tehran and the six world powers resumed negotiations in Istanbul earlier this month and are due to attend a second round of talks in Baghdad on May 23.
Both sides said the Istanbul talks were positive.