UNITED NATIONS (Reuters) -- Russia and China have quietly made clear to the Iranian government they want Tehran to change its approach to the nuclear issue and accept a U.N. atomic fuel offer, Western diplomats say.
Russia's and China's coordinated diplomatic approaches took place in Tehran around the beginning of March, according to several Western U.N. Security Council diplomats.
They said it was significant that two powers seen as blocking Western efforts to get tough on Tehran appeared to be using their influence behind the scenes to ratchet up the pressure on the Islamic Republic.
"Russia and China had a demarche in Tehran to try and get them to shift their position on the nuclear issue, particularly with regard to the Tehran Research Reactor," one diplomat told Reuters on condition of anonymity.
"The Russians and Chinese were saying that their position (on a new sanctions resolution) would depend on Iran's response to the demarches."
Another Western diplomat confirmed the Russian and Chinese "demarche," a formal diplomatic approach that can be anything from a gentle expression of displeasure to an angry protest.
"The Russians said they got nothing from Iran," the second diplomat said. "The Chinese said they got a response from the Iranians to wait a little longer and they will come up with something. But they (China) didn't get anything in the end."
Russian frustration with Iran has been growing since Tehran snubbed a U.N. nuclear watchdog plan under which the Iranians would ship most of their low-enriched uranium to Russia and France for further enrichment and processing into fuel assemblies for a Tehran reactor for medical isotopes.
Last week, Russian Foreign Minister Sergei Lavrov said Iran was letting the opportunity for normal cooperation slip away. Russian Prime Minister Vladimir Putin told U.S. Secretary of State Hillary Clinton that Moscow may support new sanctions on Iran, RIA news agency reported.
On March 4, Russian and Chinese U.N. envoys used a meeting of the Security Council to publicly urge Iran to accept the U.N. fuel plan. That proposal was meant to buy time for negotiations among the six powers and Iran by moving potential nuclear bomb material abroad.
Iran rejects Western allegations its nuclear program is a quest to develop atomic weapons and has ignored five UN resolutions ordering it to halt its enrichment program.
While China has urged Tehran to accept the International Atomic Energy Agency plan, it has repeatedly said the time was not right for new sanctions against Iran. Beijing has yet to react to a sanctions proposal drafted by Washington and circulated to Russia, China and the three European powers.
But China's refusal to engage in what Western diplomats described as "substantive discussions" on a new round of sanctions against Tehran may have come to an end, envoys said.
"The Chinese have finally agreed to participate in a conference call this week to discuss sanctions," said a Western diplomat. That call, among senior foreign ministry officials from the five permanent Security Council members and Germany, was tentatively scheduled for Wednesday.
"The Iranians clearly haven't come around after China's and Russia's demarches, so perhaps the Chinese are accepting that the time to discuss sanctions has come," one diplomat said, adding that "you never know with the Chinese."
If the Chinese agree to begin negotiating on a sanctions resolution, the measure might not be ready to put to a vote in the Security Council before June, several Western diplomats said.
The latest U.S. sanctions draft includes a proposed a ban on new Iranian banks abroad and foreign banks in Iran as well as an arms embargo with international inspections similar to one in place against North Korea, Western diplomats said.
It would also urge "vigilance" against Iran's central bank, ban insurance and reinsurance of shipments to and from Iran and would blacklist several Iranian shipping firms.