Iran expects progress will be made in talks this week with the United Nations' atomic agency, Tehran's nuclear envoy said on Monday, but Western diplomats held out little hope of an end to the deadlock.
The International Atomic Energy Agency (IAEA) has been trying for more than a year to coax Iran into letting it resume a stalled investigation into suspected atomic bomb research by Tehran, which denies any aims to make nuclear weapons.
Wednesday's talks in Vienna will be the 10th round of negotiations between the two sides since early 2012, so far without an agreement that would give the IAEA the access to sites, officials and documents it says it needs for its inquiry.
"We have the meeting with the expectation of progress of course,'' Ali Asghar Soltanieh, Iran's ambassador to the IAEA, told Reuters. "We are serious in these talks.''
But a Western diplomat, also based in the Austrian capital, said he saw "no reason at all for optimism'' in view of a series of failed meetings in the last 17 months. Other envoys also said they did not expect any breakthrough.
In May one year ago, IAEA Director General Yukiya Amano said after visiting Tehran that he expected to sign a deal with Iran soon to unblock the inquiry, but that hope was later dashed.
Western officials accuse Iran of stonewalling the IAEA, and of seeking to restrict the ability of U.N. inspectors to carry out their investigation the way they want.
Iran says the demands for access go beyond its obligations under the nuclear Non-Proliferation Treaty and that the allegations against it are based on forged intelligence.
IAEA wants base access
The IAEA-Iran talks are separate from, but still closely linked to, broader diplomatic negotiations between Tehran and six world powers aimed at resolving the decade-old dispute peacefully and prevent a new Middle East war.
Israel and the United States have warned of possible military action against Iran if diplomacy and sanctions fail to make it curb its nuclear programme.
Tehran says the programme is a purely peaceful project to generate electricity and that it is Israel, widely believed to hold the Middle East's only atomic arsenal, that threatens peace and stability in the region.
Iran and the six powers - the United States, France, Germany, Britain, Russia and China - failed to break the diplomatic impasse in their last meeting, held in early April in Kazakhstan.
Also on Wednesday, negotiators from the European Union and Iran will meet in Istanbul to discuss these diplomatic efforts, although analysts do not expect any substantive negotiations before Iran's presidential election on June 14.
Some diplomats say Iran is merely using the talks with the IAEA for leverage in the separate negotiations with world powers which, unlike the IAEA, have the power to ease sanctions that are hurting its oil-dependent economy.
The IAEA's immediate priority is to visit the Parchin military base. It suspects explosives tests relevant to nuclear weapons may have taken place there, perhaps a decade ago, and then been concealed. Tehran denies the accusation.
Iran says it must first agree with the IAEA on how the investigation should be carried out before allowing such access.
"Nothing will happen until this framework is negotiated and agreed upon,'' Soltanieh said.