The UN atomic agency said Tuesday it will hold a new round of talks with Iran on May 15 in Vienna on suspected nuclear bomb-making efforts by Tehran.

The meeting is "aimed at finalising a structured approach to resolving outstanding issues related to the possible military dimensions of Iran's nuclear programme," International Atomic Energy Agency spokeswoman Gill Tudor said.

Iran has consistently rejected as unfounded what the IAEA calls "overall, credible" evidence that until 2003 and possibly since, it conducted nuclear weapons research.

Iran denies wanting or ever having sought the bomb, and accuses the IAEA of basing its conclusions on faulty intelligence from foreign spy agencies -- intelligence it complains it has not been allowed to see.

Nine rounds of talks since the publication of a major IAEA report in November 2011 on these alleged activities have produced no breakthrough. The last was held in February.

Parallel diplomatic efforts between Iran and six major powers -- the US, China, Russia, Britain, France and Germany, known collectively as the P5+1 -- are focused more on Iran's current activities.

The latest round with the P5+1 in Almaty, Kazakhstan in early April ended with chief negotiator and EU foreign policy head Catherine Ashton saying the two sides remained "far apart".

The UN Security Council has passed multiple resolutions calling on Iran to suspend all uranium enrichment, imposing several rounds of sanctions on the Islamic republic.

Additional US and EU sanctions last year began to cause major economic problems by targeting the Persian Gulf country's vital oil sector and financial system.

Israel, the Middle East's sole if undeclared nuclear-armed state, meanwhile has refused to rule out military action on Iran, as has Washington.

Iran criticised on Tuesday a US deal to sell advanced missiles and aircraft to Israel that US Defence Secretary Chuck Hagel called a "very clear signal" that military action was still an option.

Mark Fitzpatrick, analyst at the International Institute for Strategic Studies in London, was pessimistic about the upcoming IAEA negotiations.

"After so many fruitless meetings with the IAEA to date, and particularly after the disappointing meeting in Almaty ... there is no reason to expect that Iran will finally agree to a plan for addressing the outstanding questions," Fitzpatrick told AFP.

"The IAEA is persistent in asking for a means of resolving the issues, but Iran is stubbornly insisting on tying its IAEA obligations to sanctions relief on the diplomatic track."

The new meeting between Iran and the IAEA comes ahead of the release in late May of the agency's latest quarterly report, which is expected to show that Tehran has continued to expand its nuclear programme.

In particular diplomats told AFP the report will likely say that Iran has put in more than 500 newer model "IR-2m" centrifuges at its Natanz uranium enrichment plant.

Enriched uranium is at the heart of the international community's concerns since it can be used not only for peaceful purposes such as power generation but also -- when highly purified -- in a nuclear bomb.

These more modern centrifuges, precision-engineered pieces of machinery that Iran has managed to develop despite sanctions, allow Tehran to enrich uranium at greater speeds.

Iran's atomic chief said in March that Tehran planned to install 3,000 of the centrifuges at Natanz, where some 12,500 of the older models are installed.