Major powers meet in Washington on Friday to haggle over a fourth round of U.N. sanctions against Iran, but tensions with Russia and the U.S. political calendar hang over the timing of any new measures.
The United States and its European allies France, Germany and Britain are pushing for more sanctions to punish Iran for refusing to give up sensitive nuclear work, but Russia and China are balking, say diplomats and U.S. officials involved.
Senior officials from all six nations are hoping to coordinate strategy over Tehran ahead of next week's U.N. General Assembly in New York, where foreign ministers will discuss Iran on the sidelines of the annual meeting.
Highlighting divergent views, China and Russia will be excluded from a first round of morning discussions, which will also look at Moscow's actions in Georgia, but diplomats said all six nations were expected to attend a second meeting.
"The main option here is a fourth U.N. sanctions resolution, but that is a possibility that requires Russian, Chinese and European cooperation," said a senior U.S. official, who asked not to be named as his comments were sensitive.
"Right now, Russia is a problem, let's face it ... that doesn't mean we can't work with them, but it has to be tested," said the official.
The West accuses Tehran of seeking to build a nuclear bomb, but Iran says it is enriching uranium purely for civilian atomic energy.
A senior European diplomat said while Russia would use its "usual delaying tactics," China could be a harder sell, even to get what he expected to be a very watered-down U.N resolution.
"This U.N. resolution, I can bet, will be very weak, if and when we get it ... largely symbolic because of the Russians and the Chinese," the diplomat told reporters.
He said China would refuse any major trade sanctions, Russia would not sign on to an arms embargo and the most likely outcome was an expanded number of blacklisted Iranian companies and entities.
State Department spokesman Sean McCormack said it was unclear how far the six political directors would get in hammering out specifics on Friday.
"This is probably a discussion which will be aimed at seeing where each of the individual states are in terms of the timeline of moving forward and the content of a new resolution," McCormack told reporters.
Several diplomats and U.S. officials cast doubt over Moscow's immediate support even for a weak resolution, saying U.S.-Russian tensions following Moscow's incursion into Georgia last month could make that difficult.
"We will have our wish list (sanctions) and the Russians will turn up tomorrow with their instructions to block it," said a Western diplomat, who spoke on condition of anonymity.
McCormack, however, said Russia did not want to allow Iran to build a nuclear bomb. "It is not a favor to the United States," he said of Russian cooperation in curbing Iran's nuclear ambitions.
A diplomat involved in the matter said he believed Russia would also not want to turn its back on the "P5+1", the permanent members of the U.N. Security Council and Germany, the six nations that deal with Iran's nuclear dossier.
"Iran may fall victim to the delusion that the P5+1 will fall apart. That is why we have to be unified and here, time is of the essence," the diplomat said.
All players are mindful of the Bush administration's limited time, including the Iranians who experts say are biding their time until a new U.S. president is in office in January.
"Even if they could get a resolution with teeth, would that even matter? Isn't Iran just going to continue to hold out?" said Sharon Squassoni, a nonproliferation expert from the Carnegie Endowment for International peace.
Democratic presidential candidate Barack Obama has said he would be open to direct talks with senior Iranian leaders over Tehran's nuclear program, while his Republican rival, John McCain, has taken a tougher line.
Ahead of Friday's meeting, Iran's president, Mahmoud Ahmadinejad, reiterated Tehran would not suspend its uranium enrichment work and brushed aside threats of more sanctions.