Iran signaled Thursday that it may allow United Nations inspectors to question its experts about the country's nuclear activities, potentially resolving a dispute that has blocked a nuclear deal now in the final stages of negotiation.
With pressure growing to resolve the remaining problems, Yukiya Amano, head of the International Atomic Energy Agency, the U.N.'s nuclear watchdog agency, visited Tehran to try to reach an agreement with Iranian officials on the access issues.
Iran's envoy to the IAEA, Reza Najafi, later said his government and the U.N. agency had reached a "general understanding" about cooperation and resolution of the agency demands for aggressive inspections of Iranian facilities and for access to scientists who can explain suspected past military research.
Najafi said experts would meet to sort out the details and a timetable for dealing with the issues.
A senior Iranian official in Vienna said Tehran will provide limited access to "individuals and places" related to its nuclear program, as stipulated in an arms control pact called the Additional Protocol, which is part of the Nuclear Nonproliferation Treaty. Iran is a signatory to the treaty.
"We have nothing to hide," the official told reporters.
Western diplomats viewed the developments as showing a new flexibility in Iran's position regarding intrusive inspections.
In recent weeks, Iranian supreme leader Ayatollah Ali Khamenei had repeatedly declared that Tehran wouldn't allow IAEA inspectors to question the nation's nuclear scientists and engineers, calling the demand a violation of sovereignty. Iran denies that it is seeking nuclear weapons.
But the senior official, who spoke to reporters on condition of anonymity because of the negotiations, said his government would abide by the terms of the protocol. The pact provides for so-called managed access to government sites and personnel if there is reasonable suspicion that a country is breaking nuclear rules.
Under the protocol, the access is limited to prevent the disclosure of national military secrets, a key concern for Iranian officials because at least one of its former nuclear sites is on a military base known as Parchin.
Working as a diplomatic bloc, the United States, France, Britain, Germany, Russia and China are seeking a deal with Tehran that would lift international sanctions on Iran if it agrees to rules intended to prevent it from obtaining a nuclear weapon for at least 10 to 15 years.
The Iranian official was generally optimistic that diplomats will complete the deal by their self-imposed July 7 deadline. The issues "that were difficult are now almost resolved," he said.
The IAEA long has pressed Iran to clear up questions about what the agency calls the "possible military dimensions" of its nuclear program, chiefly experiments at Parchin more than a decade ago involving nuclear triggers for a possible bomb.
U.S. intelligence officials later concluded that Iran had abandoned the research and its quest for a bomb. But the extent of the effort — and how quickly it could be rebuilt — is unknown.
The major powers also want commitments from Iran to allow inspectors to question scientists and visit sites so they can monitor enrichment and other nuclear activities over the life of the deal.
A conservative Iranian group picketed the U.N. office in Tehran to protest the demands for access, which they called a pretext for spying. One lawmaker, Mehrdad Bazrpash, told the Nasim news agency that "managed access" was "dignified espionage."
A new poll in the United States showed strong public support for the emerging deal, a key foreign policy priority for President Obama, despite skepticism that it might not prevent an Iranian nuclear capability.
The poll, by the Chicago Council on Global Affairs, found 59% of respondents favoring the "framework" deal that negotiators announced in April. Among Democrats, 74% favored the agreement, as did 57% of independents and 46% of Republicans.
At the same time, only 29% of those polled said they are confident the deal will stop Iran from obtaining a nuclear bomb in the next decade, the minimum goal Obama has set.
Special correspondent Ramin Mostaghim in Tehran contributed to this report.