As Tehran prepared to take steps Washington said would “further isolate Iran from the international community,” Russia suggested a face-saving plan that would allow Tehran to conduct less sensitive atomic activities in a joint venture with Moscow.

Accused by Western nations of running a covert atomic weapons program, Iran had frozen all work at Isfahan late last year under a deal with France, Britain and Germany. But it resumed work at the plant in August, prompting the EU’s three biggest powers to suspend talks with the Islamic republic.

Iran says its nuclear program is only for generating electricity and has resisted pressure from Europe to halt all sensitive activities, including at Isfahan, to avoid being reported to the UN Security Council for possible sanctions. A western diplomat said the Iranian UN Mission sent the International Atomic Energy Agency (IAEA) notification that the islamic republic would produce 150 drums of raw yellowcake uranium staring next week, Reuters reported. Once converted into uranium hexafluoride (UF6) gas and then enriched, this would theoretically be enough to create fuel for one nuclear bomb.

However, diplomats close to the IAEA say the quality of the UF6 produced at Isfahan so far is so poor as to be unusable, casting doubt on Tehran’s threats to begin work on uranium enrichment, the most sensitive part of the nuclear fuel cycle, Reuters reported.

In an attempt to avoid an escalating international row, Russia has proposed it host a uranium conversion and enrichment joint venture with Iran, diplomats said. This would allow Iran to produce uranium tetrafluoride (UF4) at Isfahan, which would then be shipped to Russia for conversion into UF6 and enrichment. Tehran is not opposed to the Russian-conceived idea, but wants the joint venture to be located in Iran, he said. Diplomats say the Russian plan would be supported by the Europeans and by IAEA head Mohamed ElBaradei, provided Tehran agreed to a full suspension of all other sensitive nuclear activities.

US State Department spokesman Sean McCormack described the plan to convert more uranium as “yet another step that takes Iran in the wrong direction and serves only to further isolate Iran from the international community,” Reuters reported.