Ankara: Iran’s Supreme Leader Ayatollah Ali Khamenei said on Wednesday Tehran would not accept “unreasonable demands” by world powers during negotiations over its disputed nuclear programme, and ruled out letting inspectors interview its atomic scientists.

The comments, broadcast live on state TV, were the latest in a series of forthright statements on inspections in the countdown to a June 30 deadline to resolve a decade-old standoff over Iran’s nuclear work.

“We will never yield to pressure ... We will not accept unreasonable demands ... Iran will not give access to its (nuclear) scientists,” Khamenei said.

“We will not allow the privacy of our nuclear scientists or any other important issue to be violated.” Khamenei, who has the final say for Iran on any deal, last month ruled out any “extraordinary supervision measures” over nuclear activities and said military sites could not be inspected.

The UN International Atomic Energy Agency (IAEA) has been trying to investigate Western allegations that Iran has worked on designing a nuclear warhead. Iran says its nuclear programme is peaceful and that it is working with the IAEA to clear up any suspicions.

UN inspectors regularly monitor Iran’s declared nuclear facilities, but the IAEA has complained for years of a lack of access to sites, equipment, documents and people relevant to its probe.

Western officials say Iran must step up cooperation with the IAEA if it wants to reach a broader diplomatic deal with world powers that would gradually end crippling financial and other sanctions on the oil producer.

“They say we should let them interview our nuclear scientists. This means interrogation,” Khamenei said.

“I will not let foreigners talk to our scientists and to interrogate our dear children ... who brought us this extensive (nuclear)knowledge.” Iran has yet to answer questions about two areas of the investigation into alleged research activities that could be applicable to any attempt to make nuclear bombs - explosives testing and neutron calculations.

Iran reached a tentative deal with the powers on April 2 to allow UN inspectors to carry out more intrusive, short-notice inspections under an “Additional Protocol” to the Non-Proliferation Treaty. But there have been sharply differing interpretations from both sides on the details of that access.

Negotiators from Iran and the powers will meet in Vienna on Wednesday to try to iron out remaining differences, including the timing of sanctions relief and the future of Iran’s atomic research and development programme.

Talks between EU political director Helga Schmid and Iranian negotiators Abbas Araqchi and Majid Takht-Ravanchi will run until Friday, with experts meeting in parallel to discuss technical annexes, the EU said in a statement.