"We're in a holding pattern for this meeting" opening Monday of the 35-nation International Atomic Energy Agency (IAEA) board of governors, a Western diplomat, who asked not to be named, told AFP.
A tough Washington-inspired IAEA board resolution in March that condemned Iran for omitting to report its work into sophisticated P-2 centrifuges which can make bomb-grade uranium led Iran to delay crucial agency investigations, a delay that makes it difficult for the IAEA to draw conclusions this June.
The United States looks ready to sign on this time to a British-French-German draft resolution that sharply criticizes Iran for failing to answer questions about alleged nuclear weapons activities but presses for continued cooperation with Tehran, diplomats said.
The resolution "deplores" the fact that that Iran's "cooperation has not been complete, timely and proactive," according to extracts read to AFP by diplomats.
But it "acknowledges Iranian cooperation in responding to agency requests for access to locations including workshops" on military sites.
"It is a message. It makes it clear what we expect from them", a diplomat said.
The resolution is modeled on a report IAEA director general Mohamed ElBaradei submitted ahead of the board meeting, the diplomat said.
The United States charges that Iran is secretly trying to develop nuclear weapons and should be taken to the UN Security Council for possible sanctions.
But Washington does not have support at the IAEA for its hardline stance and is also hampered by the situation in Iraq, where it needs Iran's backing to not further inflame the Shiite population, diplomats said.
In addition, the so-called EU-3 of Britain, France and Germany have since last October backed an agreement they worked out with Iran for cooperation in resolving questions about its nuclear program.
A US official said the United States "thinks we're going to get a firmly worded resolution out of the IAEA board of governors."
A Western diplomat said Washington "was involved to at least a degree" in drafting the EU-3 resolution and felt the draft had "strong language and was moving towards where the United States wants to be."
The United States clearly expects more revelations to come forth of Iran hiding weapons development, diplomats said.
This could mean that the showdown over Iran at the IAEA may only be on hold until after the US presidential election in November, the diplomats said.
Diplomats said even the EU-3 was getting impatient with Iran, as the IAEA has been investigating the Iranian program since February 2003 with Iran consistently failing to deliver on promises for full disclosure of its atomic activities.
"There are two main points they (the Iranians) have to resolve, as the report makes clear. These are research into sophisticated P2 centrifuges that can make bomb-grade uranium and what is the source of highly enriched uranium contamination which IAEA inspectors have found", a Western diplomat said.
Another Western diplomat said: "At some point we either have to have a breakthrough and progress or have failure and take the issue to the Security Council."
Iran's clerical regime repeated on June 2 its claim that its nuclear program is for peaceful purposes and that there is no clandestine effort.
Iran's top national security official Hassan Rowhani told reporters: "Iran's nuclear dossier is on the way to being sorted out and there is nothing very important that is pending."
But the Euro-3 resolution "deeply regrets that Iran has not fully implemented" promises to halt all activities related to enriching uranium, including "taking steps to produce" uranium hexafluoride, an enrichment fuel, and "continuing to produce centrifuge components."