By Yeganeh Torbati and Fredrik Dahl
LONDON/VIENNA (Reuters) - The head of the U.N. nuclear watchdog is considering an invitation to visit Tehran for scheduled talks, a possible sign of progress in a long-stalled investigation into suspected nuclear arms research by Iran.
Iranian state television said International Atomic Energy Agency Director-General Yukiya Amano was expected in Tehran on November 11, but the IAEA said only that an invitation was "being considered".
After years of worsening confrontation with the West, Iran has switched to a more conciliatory mode in diplomacy on its nuclear activities since the relatively moderate Hassan Rouhani was elected president in June.
The IAEA's talks with Iran are intended to set up an inspection regime to allow it to prove or disprove Western fears that Iran's nuclear program includes weapons research, but a series of meetings since January 2012 have led nowhere.
The Islamic Republic denies seeking nuclear weapons, saying it wants only civilian atomic energy.
Ali Akbar Salehi, the head of Iran's atomic energy organization, said he hoped for an agreement during Amano's visit, state television said on its website, giving no details.
The U.N. agency wants access to sites, officials and documents in Iran including the Parchin military base, where it believes nuclear-related explosives tests might have taken place, possibly a decade ago.
The discussions are separate from broader negotiations between Iran and six world powers that resumed in Geneva last month and will continue there on November 7 and 8.
LAST VISIT A FAILURE
Amano has not been to the Iranian capital since May 2012, when he returned saying he expected to sign a deal soon, only to see it fail to materialize.
Diplomats say he would probably want to be confident of concrete progress before repeating the high-profile trip.
IAEA spokeswoman Gill Tudor said only that Amano had been invited to Tehran, "and this is being considered".
Iran says it is refining uranium only to fuel future power plants and an existing medical research reactor. But its refusal so far to curb sensitive nuclear work and its lack of transparency toward the IAEA have drawn heavy sanctions.
IAEA and Iranian officials described talks in Vienna last week as "very productive" and agreed to meet again on November 11.
Salehi said he had invited Amano to visit on that day and that Amano had expressed his "inclination" to do so, state television said. Salehi said he hoped that he and Amano would be able to issue a joint statement on a deal.
"The International Atomic Energy Agency has moved forward with a positive approach and, as before, we will continue to collaborate in a transparent manner and we are more than ever ready to cooperate with the agency," Salehi told reporters, according to the state news agency IRNA.
Iran said last week that it had put forward new proposals to the U.N. agency after pledging "a new approach" to easing international concerns about its nuclear program.
Western experts say that Iran will probably agree to cooperate fully with the IAEA's investigation only as part of a broader settlement with the United States, France, Russia, China, Britain and Germany that wins it relief from sanctions.
(Editing by Mark Heinrich and Kevin Liffey)