Western powers hope to win Russian and Chinese backing for rebuking Iran at the U.N. nuclear agency next week over Tehran's failure to address mounting fears that it is secretly bent on acquiring nuclear weapons capability, diplomats say.
Seeking to ward off any such diplomatic action, Iran has warned its opponents and others against making provocative statements at the March 5-9 meeting of the 35-nation governing board of the International Atomic Energy Agency (IAEA).
Western envoys say the lack of progress at talks this year between the IAEA and Iran and Tehran's acceleration of sensitive atomic activity mean the board should respond to the country's defiance of increased international pressure.
But they make clear they want broad support for any new board resolution and especially from Russia and China, which have backed four rounds of U.N. sanctions since 2006 but criticised unilateral Western punitive steps against Iran.
An IAEA resolution, while containing no concrete measures, would be aimed at sending a united message to Iran that it must stop stonewalling the U.N. agency's investigation into possible military dimensions to its nuclear programme, diplomats say.
We think there needs to be a resolution that makes clear ... that Iran needs to do more, a lot more, to comply with the agency's requirements, a senior Western official said.
He said Iran's lack of cooperation with a senior IAEA team, during two rounds of meetings in Tehran in January and February, represented a gigantic slap in the face for the IAEA.
But an ambassador of a non-Western state showed a lack of enthusiasm, saying a resolution that was adopted at the most recent board meeting in November, and voiced increasing concern about Iran's nuclear programme, was still relevant.
It was more important, he said, to create favourable conditions for a resumption of wider nuclear negotiations between Iran and the six major powers - the United States, Russia, China, Britain, France and Germany.
They are discussing how to react to an Iranian offer last month to restart talks which have been frozen for more than a year, as Iran presses ahead with its nuclear programme.
A report by the IAEA last week said Iran was significantly stepping up uranium enrichment, a finding that sent oil prices higher on fears tensions between Tehran and the West could escalate into military conflict.
Israel has threatened to launch strikes to prevent Iran getting the bomb, saying Tehran's continued technological progress means it could soon pass into a zone of immunity. U.S. officials say sanctions should be given time to work.
IRAN'S OUT OF THE BLUE OFFER
The IAEA's report showed that Iran had tripled output of uranium enriched to a fissile concentration of 20 percent, well above what is usually needed to fuel nuclear power plants.
Iran says the more highly refined uranium will replenish the dwindling special fuel stocks of a reactor that produces medicinal isotopes.
But 20 percent enrichment, experts say, represents most of the effort needed to attain the 90 percent threshold required for nuclear explosions.
Much of this work is carried out deep inside a mountain at Iran's underground Fordow facility to better shield it against military strikes, and it is preparing for a further expansion.
Iran is now believed to be capable of increasing its output capacity of 20 pct uranium four-fold over a fairly short period of time, a Western diplomat said.
The IAEA report showed total production so far of this higher-grade material at about 110 kg, roughly half way to the quantity Western experts say would be sufficient for one bomb.
Iran denies Western accusations that it is seeking weapons of mass destruction, saying it needs higher-grade uranium for a the Tehran research reactor making isotopes for cancer care.
Iran's envoy to the IAEA, Ali Asghar Soltanieh, insisted that substantial progress was made in the Tehran meetings.
There shouldn't be any provocative statements. There should be encouraging statements for Iran and the agency to continue the work, he told reporters this week.
During the two rounds of talks in the Iranian capital, Iran did not grant IAEA requests to visit the Parchin military facility, seen as central for its investigation.
The November IAEA report said the agency had information that Iran had built a large containment chamber at Parchin to conduct high-explosives tests which, it said, were strong indicators of possible weapon development.
Vienna-based diplomats said the agency team at the talks had turned down a last-minute offer for them to go to another site, Marivan, also mentioned in the IAEA report as it detailed research activities relevant for atomic bombs.
But that offer came out of the blue and the agency team was completely unprepared to go there, one envoy said.
The IAEA board was also expected to touch on North Korea's announcement this week that it would suspend major elements of its nuclear weapons programme and allow U.N. inspectors back for the first time in three years.
On another sensitive nuclear issue, diplomats said Syria had once again made clear, in an exchange of letters with the IAEA, that it was not in a position to engage with the agency in its long-stalled investigation into Damascus's atomic activity.
I simply can't imagine that there is any capacity in Syria at the moment to mobilise any sort of practical response on this, the Western diplomat said, referring to President Bashar al-Assad's ongoing campaign to stamp out a popular uprising.
(Editing by Mark Heinrich)