By Fredrik Dahl
VIENNA (Reuters) - The U.N. nuclear agency expects to reach a deal with Iran next month enabling it to resume a stalled probe into suspected nuclear weapon research in the Islamic state, the chief U.N. inspector said after returning from Tehran on Friday.
Even though the International Atomic Energy Agency failed to gain access to the Parchin military complex during Thursday's visit to the Iranian capital as requested, IAEA delegation head Herman Nackaerts said progress had been made.
"We had good meetings," Nackaerts, deputy director general of the U.N. watchdog, told reporters at Vienna airport.
World powers seeking to resolve a decade-old dispute over Iran's atomic activity and avert the threat of a new Middle East war closely watched the IAEA-Iran talks for any indication of Iranian readiness to finally start addressing their concerns.
U.S. ally Israel - believed to have the Middle East's only nuclear arsenal - has threatened military action if diplomacy and economic sanctions intended to halt Iran's uranium enrichment work do not resolve the standoff.
The IAEA and Iran, which denies Western allegations it is seeking to develop a capability to assemble nuclear weapons, will meet again on January 16, Nackaerts said.
"We expect to finalize the structured approach and start implementing it then shortly after that," he said, referring to a framework agreement on how to address the IAEA's suspicions about possible military dimensions to Iran's nuclear program.
Nackaerts did not give details on what had been achieved, but one stumbling block in previous, mostly fruitless meetings was Iran's request for access to intelligence documents at the basis of the U.N. agency's mounting concerns.
The IAEA said also after talks in May that it expected an agreement soon, but that failed to materialize.
"We have now had so many false starts that there are grounds to be skeptical," said Shashank Joshi, a senior fellow and Middle East specialist at the Royal United Services Institute.
Western diplomats, who often accused Iran of stonewalling and playing for time in its dealings with the IAEA, are likely to react cautiously and tell Tehran it must engage in substance on the agency's inquiry and immediately give it the access to sites, officials and documents it needs for its inquiry.
PARCHIN VISIT STILL "USEFUL"
"There will likely be many in Washington and Israel skeptical that this ... is anything but a delaying tactic on Iran's part," Miles Pomper, senior research associate at the James Martin Center for Nonproliferation Studies, said.
Iran says its nuclear program is a peaceful bid to generate electricity. But its refusal to curb activity which can have both civilian and military purposes and lack of openness with the IAEA have drawn increasingly tough Western sanctions.
The IAEA - which said before the trip it hoped to visit the Parchin site - was unable to go there this time but it would be part of the "structured approach" accord, Nackaerts said.
The Vienna-based U.N. agency believes Iran has conducted explosives tests with possible nuclear applications at Parchin, southeast of Tehran, and has repeatedly asked for access. Iran says Parchin is a conventional military site and has dismissed allegations that it has tried to clean up the site before any visit. [ID:nL5E8NC8Q1] It says it must first agree a framework deal with the IAEA before allowing access to sites.
Western diplomats say Iran has carried out extensive work at Parchin in the past year, including demolition of buildings and removal of soil, to cleanse it of any traces of illicit activity. The IAEA says a visit would still be useful.
The IAEA-Iran talks are separate from but closely linked to broader efforts by six world powers to resolve the nuclear row.
Analysts and diplomats say there is now a window of opportunity to make a renewed diplomatic push after last month's re-election of U.S. President Barack Obama.
The six powers - the United States, Britain, France, Germany, Russia and China - want Iran to curb its uranium enrichment program and cooperate fully with the IAEA. Iran wants the West to lift sanctions hurting its economy.
A member of Iran's negotiation team said talks between Iran and the powers were unlikely to yield results.
"Personally speaking, I am not optimistic," Mostafa Dolatyar told reporters at the Iranian embassy in New Delhi on Friday.
Daryl Kimball, of the Washington-based Arms Control Association advocacy group, said some sanctions relief for Iran would be more likely if it "would immediately cooperate with the IAEA on inspections of key sites and personnel to ensure that past weapons-related experiments have been discontinued."
(Additional reporting by Nidhi Verma and Frank Jack Daniel in New Delhi; Editing by Angus MacSwan)