The most tangible accomplishment from the last meeting between Iran and world powers was simply an agreement to talk again about Tehran's nuclear ambitions. When negotiations resume later this month, both sides will be groping for ways to keep the dialogue alive.

It could be a clear challenge. Iran wants what the West appears unwilling to give: easing sanctions to push the talks forward. Washington and allies are demanding concessions that Iran finds far too lopsided: scaling back its ability to make nuclear fuel in exchange for some modest givebacks such as spare airline parts.

About the only strong force pushing them toward common ground is the likelihood that failure would bring fresh calls from Israel and elsewhere for military action. The chief of staff for Israel's military, Lt. Gen. Benny Gantz, said Tuesday that a "super-ready" military threat is needed in tandem with diplomatic initiatives.

Gantz also hinted at other "disturbances" to Iran's nuclear program, which was certain to raise speculation about cyberwarfare and assassinations of Iranian scientists that Tehran has blamed on Israel's Mossad spy agency.

"This is both a poker game and a chess match on all sides," said Bruno Tertrais, senior researcher at the Foundation for Strategic Research in Paris. "There's bluffing like with poker. There's the effort to plot several moves ahead like in chess."

"The only real tactic agreement, it seems, is that nobody wants the talks to fall apart," he added. "They want — they need — to find a way to keep them going."

Iran will likely head to the June 18-19 talks in Moscow with the same general demands that fell flat last month in Baghdad, the first main negotiating session since the effort was revived in April.

At the top of Iran's list is having the U.S. and Europe roll back on toughened sanctions targeting Iran's critical oil exports and blackballing the country from international banking networks. The 27-nation European Union, which recently accounted for 18 percent of Iran's oil shipments, plans to begin a boycott July 1.

The six-nation bloc on the other side — the five permanent U.N. Security Council members plus Germany — also seems to be holding fast to its position. The focus is getting Iran to shut down its highest-level uranium enrichment.

The West and others say the 20 percent enriched uranium used in Iran's medical research reactor is just steps away from being boosted to weapons-grade material. In return for fewer sanctions, Iran would be allowed to continue — temporarily at least — to make lower-level fuel for its lone power-generating reactor and receive airplane parts and other goods now restricted by sanctions.

Iran insists it has no intention of making nuclear arms and says its reactors are only for energy and medical applications.

Iranian envoys quickly dismissed the world powers' blueprint as unacceptable. "Diamonds in return for peanuts," scoffed former Iranian nuclear negotiator Hossein Mousavian, who is now a research scholar at Princeton University.

Iranian political commentator Morad Enadi, who is close to the ruling system, predicted there is a risk of "attrition" taking root at the Moscow talks without greater flexibility on all sides.

In a glimpse into Iran's high-level perceptions of the showdown, Supreme Leader Ayatollah Ali Khamenei on Sunday described the sanctions as the West's attempt to "topple the Islamic system" and not just to rein in Tehran's nuclear advancements. Other Iranian officials have increased their calls for Western acknowledgment that Iran has the "right" to enrich uranium as a signatory of the U.N. treaty overseeing the spread of nuclear technology.

The message is that Iran is seeking a clear roadmap from the West on what it expects of Iran and what it will get in return.

"Success of talks in Moscow depends on drawing up a comprehensive agenda," Iran's No. 2 nuclear negotiator, Ali Bagheri, was quoted Wednesday as saying by Iranian media.

Also Wednesday, Iranian President Mahmoud Ahmadinejad was in Beijing for a regional security conference that included allies China and Russia, both part of the nuclear talks.

But a priority item from the Western side — inspection access to an Iranian military base — is already a major complication.

On Tuesday, the chief U.S. envoy to the U.N. nuclear agency challenged Iran to ease suspicions it had conducted nuclear weapons-related tests at the Parchin base southeast of Tehran. Iran last month reached a tentative accord to allow teams from the International Atomic Energy Agency into the site, but no timetable has been set.

The agency also has noted satellite photos that suggest extensive earth-moving and cleaning work at Parchin that strengthened fears Iran was trying to cover up evidence of secret work on high explosives used to set off a nuclear charge. Iran has denied it carried out such tests, and said no cleaning operation can remove radioactive residue.

"If Iran has nothing to hide, why deny the agency access and carry out these apparent cleanup efforts?" asked Robert Wood at the IAEA headquarters in Vienna. Iran says it is willing to allow IAEA to visit Parchin as a confidence-building measure, but first wants to set specific guidelines for an inspection.

Wood also hammered on another key Western demand: Halting enrichment work at bunker-like labs carved into a mountainside about 120 kilometers (70 miles) south of Tehran. The Fordo site is far smaller than Iran's main enrichment facility but it is apparently engaged in the highest-level production. U.N. nuclear watchdogs are currently studying internal reports that radioactive material even higher than 20 percent enrichment was detected at the site. Tehran called it a technical glitch.

"Enrichment per se has never been the problem," said the researcher Tertrais. "Germany and Japan have enrichment programs, but do not have nuclear weapons. It's all about suspicions. Iran has to begin to put those suspicions to rest."


Murphy reported from Dubai, United Arab Emirates.