Vienna: Tehran’s top nuclear negotiator said on Tuesday he hoped diplomacy resuming this week will yield results before a self-imposed deadline for a final deal to curtail Iran’s atomic programme expires at the end of June.

“We hope we can pull together an agreement before July 1,” Abbas Araqchi was quoted as saying by Iran’s Mehr news agency as he met European officials in Vienna.

Diplomats are trying to fill gaps in an April 2 framework pact that would curb Iran’s nuclear programme, allaying Western fears it may be geared to developing an atomic bomb capability, in return for relief from international sanctions.

Iran, which denies seeking nuclear weapons, has said sanctions must be rescinded as soon as any final deal is signed.

The United States wants a gradual lifting of restrictions — a big sticking point left unresolved so far.

The framework deal did not spell out all details about the future of Iran’s atomic research and development programme, the exact scope of the UN atomic watchdog’s monitoring regime, and what kind of uranium stockpile Tehran will be allowed to keep.

“We have to abide by the solutions and agreements that we reached in Lausanne, and we will only negotiate in that framework,” Araqchi said, referring to the interim deal between Iran and the United States, Russia, China, France, Britain and Germany.

This week’s diplomatic flurry sees European Union Political Director Helga Schmid meet Araqchi and Iranian diplomat Madjid Takht Ravanchi in Vienna on Tuesday.

Chief US negotiator Wendy Sherman is due to travel to Vienna on Wednesday to join the talks, while the other big powers send officials on Friday.

US Secretary of State John Kerry was to meet Russian President Vladimir Putin in Russia on Tuesday and was expected to discuss the Iran nuclear talks with him.

The White House scrambled on Monday to counter perceptions that the Saudi king’s absence from a summit later this week could undermine US efforts to assure Gulf states it remains committed to their security against Iran.