The UN atomic watchdog begins its traditional September board meeting in Vienna on Monday to discuss the current stalemate in its long-running investigation into Iran's controversial atomic drive.
The meeting, which is slated to run all week but could be wrapped up as early as Wednesday, according to some diplomats, is also expected to hear an update on state of the International Atomic Energy Agency's probe into Syria.
Syria -- which the US alleges had been building a secret nuclear facility until it was destroyed in a bombing raid by Israel -- is not officially on the agenda.
Nevertheless, IAEA Director General Mohamed ElBaradei is expected to update the 35-member board on the state of the investigation during his opening address on Monday.
Finally, the governors are set to discuss ElBaradei's latest report on Libya, which abandoned a clandestine nuclear weapons programme in 2003 and has cooperated openly and fully with the agency in clearing up any outstanding questions ever since.
As at previous board meetings, it will be the Iran dossier that will dominate proceedings after a new report by ElBaradei accused Tehran of stalling the IAEA's investigation, refusing to provide access to documentation, individuals or sites which could reveal the true nature of its activities.
The watchdog has been investigating the Islamic republic's contested nuclear drive for five years, but has so far been unable to determine whether the programme is entirely peaceful as Iran claims.
At the moment, the agency and Iran are -- in the words of a senior official -- "gridlocked" over Tehran's refusal to provide proof that it was not involved in studies to make a nuclear warhead, as a wide range of intelligence suggests it was.
A number of diplomats accredited to the IAEA have spoken of the agency's increasing frustration that Tehran has done little more than dismiss the so-called "alleged studies" as "false" and "fabricated".
The IAEA said it has obtained important new indications that an unidentified foreign expert may have assisted Iran in experiments on high explosive testing "suitable for an implosion type nuclear device".
Diplomats who attended a special technical briefing this week said the IAEA's head of inspections in the Middle East region, Herman Naeckerts, showed them documents and photographs suggesting Iran secretly tried to modify a missile cone to fit a nuclear bomb.
The US envoy to the IAEA, Gregory Schulte, told reporters afterwards that Naeckerts had said the information was "in their words, 'very credible', unquote, and they have asked Iran to provide 'substantive responses', unquote."
Furthermore, Iran has refused IAEA requests to interview engineers involved in the work and visit their ostensibly civilian workshops.
For its part, Iran continues to assert that the intelligence is forged.
"This matter is over, as far as we are concerned," said Iranian ambassador Ali Asghar Soltanieh.
Another moot point for the IAEA is Iran's refusal to suspend uranium enrichment, a process that can be used to make the fissile material for an atomic bomb.
Indeed, Iran has installed additional cascades of uranium-enriching centrifuges, bringing the number up and running to close to 4,000, and was testing more advanced centrifuges as well.
Among the other topics up for discussion, Syria is not an official agenda item, since the findings of a one-off visit by IAEA inspectors in June to the bombed site of Al-Kibar have not been fully evaluated yet and Damascus is blocking IAEA requests to visit other suspicious sites.
Nevertheless, ElBaradei is expected to mention in his opening address and diplomats said Syria could be discussed in more depth at the next board meeting in November.
The matter of ElBaradei's successor -- the Egyptian diplomat recently announced he would not be standing for a fourth term when his current term expires on November 30, 2009 -- is to be discussed at a special one-day board meeting on October 6.
Diplomats have said that two firm candidates have emerged so far: South African ambassador Abdul Samat Minty and Japan's Yukiya Amano.
The closing date for applications is December 31, 2008, with ElBaradei's successor to be appointed in June 2009 "at the latest".
That appointment will then be put to next year's general conference for final approval.