on Sunday rejected demands
the West is reportedly to submit at talks due to take place in days, saying it will neither close its Fordo nuclear bunker nor give up higher-level uranium enrichment.
Those two demands, outlined by European and US diplomats to The New York Times newspaper, were "irrational," the head of Iran's Atomic Energy Organization, Fereydoon Abbasi Davani, told ISNA news agency in a lengthy interview.
Fordo, an underground bunker near the holy city of Qom, "is built underground because of sanctions and the threats of attacks," he pointed out.
"If they do not threaten us and guarantee that no aggression will occur, then there would be no need for countries to build facilities underground. They should change their behavior and language," he said.
Iran's enrichment of uranium to 20 percent purity would likewise continue, despite unease from members of the P5+1 group - the five permanent UN Security Council members plus Germany - that it produced uranium stock just a few steps short of military-grade 90-percent purity, Abbasi Davani said.
"We do not see any rationale for such a request from the P5+1," he said.
But, he added, "We will not produce 20 percent enrichment fuel more than what we need, because it is not in our benefit to produce and keep it."
Prime Minister Benjamin Netanyahu said on Sunday to visiting Italian Prime Minister Mario Monti: "Our policy on Iran has not changed ... We will follow the talks. The demands of Iran must be clear: to take away the enriched material, halt the enrichment and dismantle the facility in Qom."
Iranian media said the talks, which collapsed more than a year ago, would be held in Istanbul on Friday.
"After weeks of debates, Iran and the six world powers agreed to attend a first meeting in Istanbul," the semi-official Fars news agency reported, citing unnamed sources. State-run English language Press TV carried the same report.
The Fars news agency also said the sides had agreed to a second round of talks in Baghdad if there was progress in Turkey. There was no immediate comment on the venue from the world powers.
The New York Times quoted unnamed US and EU diplomats as saying the West would call for Fordo to be closed immediately and dismantled, and for uranium enrichment to 20 percent to be halted and for existing stockpiles to be shipped out of Iran.
The demands would be the opening move in what US President Barack Obama has called Iran's "last chance" to resolve the showdown over the nuclear issue diplomatically, the report said.
"We have no idea how the Iranians will react," the paper quoted one senior administration official as saying. "We probably won't know after the first meeting."
Iranian President Mahmoud Ahmadinejad said in a statement on his official website: Iran is ready for negotiations and welcomes any suggestion for cooperation."
He said "Iran has practical suggestions for the upcoming meeting," but did not elaborate.
Ahmadinejad stressed again that his country was not seeking atomic weapons and he noted that Iran's nuclear activities were under the supervision of the International Atomic Energy Agency.
He also underlined that the United States was promoting the interests of Israel, the Middle East's sole if undeclared nuclear weapons state.
"The parties who are against the Iranian people have very close relations with some nations who have atomic bombs, but they are constantly pressuring us on some pretext of Iran supposedly building an atomic bomb in the far future," he said.
Iran, Ahmadinejad said in a separate speech carried by his website, "will continue with force on the path it has embarked on.
AFP and Reuters contributed to this report