VIENNA, Austria - Six world powers have readied a resolution critical of Iran's nuclear program, diplomats said yesterday as Tehran suggested it was still ready to discuss a U.N.-backed plan meant to delay Iran's ability to make a nuclear weapon.

The plan would have Iran export its uranium for enrichment in Russia and France, for conversion into fuel rods to be returned to Iran about a year later.

The six powers embraced the plan because it would have committed Iran to ship out about 70 percent of its enriched-uranium stockpile. Tehran initially appeared to agree, only to backtrack in recent weeks.

Foreign Ministry spokesman Ramin Mehmanparast said yesterday that no one in Iran "ever said ... that we are opposed to shipping out our uranium," adding, "What has been discussed is the method to ship out this material."

He did not indicate whether he was suggesting that Iran sought to ship out small batches, then wait until they were turned into fuel rods before exporting the next small batch. The West has rejected that approach as defeating a main purpose of the plan: stripping Tehran of most of its weapons-capable material.

Iranian officials have accused the West of breaking past promises to supply technology to Iran. They say they don't trust that the West will eventually send back the fuel rods if Iran lets its uranium abroad.

In Vienna, the six-power move to criticize Iran in the form of a draft resolution for a coming International Atomic Energy Agency board meeting reflected international exasperation with Iran's perceived delaying tactics and refusal to heed pressure to compromise on its nuclear program.

Britain's Foreign Office urged that "the strongest possible signal to Iran" be sent that its actions "are a matter of grave concern."

The diplomats said the draft called on Iran to be more open about its nuclear plans after its recent revelation that it had secretly nearly completed a new uranium-enrichment facility.

The draft urges Iran to open its program to wider perusal by the IAEA. It also calls on Iran to answer all outstanding questions on that enrichment plant, comply with U.N. Security Council demands that it suspend enrichment and further plant construction, and stop stonewalling an IAEA probe of allegations it tried to develop nuclear weapons.

The development is significant because it groups Russia and China with the four Western powers - the United States, Britain, France, and Germany - in unified criticism of Iran's nuclear program.