By Michelle Moghtader and Fredrik Dahl
DUBAI/VIENNA (Reuters) - Iran held talks with the U.N. nuclear watchdog on Sunday about its investigation into suspicions that Tehran has conducted atomic bomb research, and is still committed to implementing agreed transparency measures, official media reported on Monday.
Iran's envoy to the International Atomic Energy Agency, Reza Najafi, appeared to acknowledge, however, that Tehran had missed a deadline of Aug.25 to meet five requests from the International Atomic Energy Agency about its nuclear programme.
"Iran is in the process of implementing the five agreed steps," the official IRNA news agency quoted him as saying.
Diplomats in Vienna told Reuters last week that Iran had apparently failed to meet the target date, but said contacts were continuing.
Western officials say addressing the IAEA's concerns is vital for Iran to have any chance of success in parallel negotiations to end a decade-old nuclear standoff with the West.
Iran's Press TV website said Iranian and IAEA experts had met in Tehran on Sunday. Najafi said they had exchanged information in "serious" discussions that would continue soon, IRNA reported.
Diplomats in Vienna said they had heard about the IAEA's visit to Tehran, but had no details so far. The IAEA itself declined to comment, suggesting any information would be included in its quarterly report on Iran, expected this week.
The Vienna-based U.N. agency has for years been investigating intelligence suggesting Iran has carried out experiments and other activities that could be used to develop nuclear weapons.
Iran says its nuclear programme is entirely peaceful, but Western countries fear its real aim is to develop a weapons capability, and have imposed economic sanctions.
DETONATOR DEVELOPMENT
As part of accord reached in November in an attempt to revive the long-stalled IAEA investigation, Tehran agreed in May to carry out five specific steps by late August.
They included providing information on alleged experiments on explosives that could be used for an atomic device, and on studies related to calculating nuclear explosive yields.
While denying such allegations as baseless and fabricated, Iran has been promising to cooperate with the IAEA since Hassan Rouhani, seen as a pragmatist, was elected president in 2013.
"Three out of the five steps have been completely implemented," Najafi said, without giving details.
Apart from the information, Iran also agreed to give IAEA inspectors access to sites including a centrifuge research and development facility by late August.
In 2011, the IAEA published a report that included intelligence indicating Iran had a nuclear weapons research programme that was halted in 2003 when it came under increased international pressure. The intelligence suggested some activities may later have resumed.
After years of what the West saw as Iranian stonewalling, Iran as a first step in May gave the IAEA information about why it was developing "bridge wire" detonators, which can be used to set off atomic explosive devices. Iran says they are for civilian use, and wants this topic in the investigation closed.
In mid-July, the separate negotiations on a wider diplomatic settlement between Iran and the United States, France, Germany, Britain, China and Russia were extended until late November.
(Editing by Robin Pomeroy and Kevin Liffey)